Everest isn’t a very technical climb - it’s mostly just a long walk in very very harsh conditions.
The record on Everest right now is that one out of every 10 people attempting the summit is going to die. Your odds of getting yourself down alive are not very good. The odds of you getting down alive while carrying another person are much worse.
There are these absolutely frightening (to me, at least) descriptions from people who have climbed Everest that even with supplemental oxygen, they find themselves having to take two, three, six, or even ten breaths between each step. It typically takes more than twelve hours to walk the final one mile.
In the death zone (above 26,000 feet), there’s not enough oxygen to sustain human life indefinitely; without supplemental oxygen, anyone who stays at that altitude will eventually die. Most climbers at those altitudes tend to carry supplemental oxygen to stave off complete mental stupidity and also to jack up their metabolism enough to stave off hypothermia and frostbite (keeping warm seems to be one of the main challenges in the death zone), but you can only carry so much; even with it, the ascent is still a monumental struggle. So if you’re on supplemental oxygen, and barely able to get yourself down under the best circumstances - managing tricky footing and rock scrambles, all under a mental fog and with muscles barely able to do your bidding - it’s going to be nearly impossible to assist someone else who can’t even summon the strength to stand up.
In the hypothetical, yes, you save the other person and climb Everest again some other time. In a real-world situation like this one, the stricken climber is almost certainly going to die, and the only question is whether you die trying to save him or do what you can to make sure you survive. That’s not a very hard choice.
Plus it’s not just a steep hill. There are overhangs, sheer rock faces, things that are dangerous to the able-bodied and mentally sharp. (IIRC from what I’ve read, one route even has a metal ladder lashed in place as a bridge in one spot?) If you have someone with you who’s suffering from oxygen deprivation, frostbite, maybe even snowblindness, you actually do risk killing both of you.
Not fighting the hypothetical: Stop and save the other climber.
Reality: Ignoring the fact that I wouldn’t be up there and every non-world-class climber who hires a professional tour group to near-literally drag him or her up that mountain adds to the danger for everyone else on that mountain (I’ve read accounts with people stuck in a single-file line behind slowpokes who are barely competent at climbing and worrying where they’re going to be stuck on the mountain when the snow hits), it would be extremely dangerous to try to bring someone down with me and hopefully my brain would be able to analyze the situation properly.
There isn’t enough oxygen. If you could transport yourself right now from sea level to the summit of Everest, you would pass out and die within a couple of minutes. Climbers spend months acclimating themselves to the thinner air, slowly moving higher and higher over the weeks and sometimes even that by itself proves fatal. By the time you’re ready to start the final push to the top you’re in terrible shape, physically and mentally. You’ve possibly endured constant headaches, haven’t been sleeping well, you are slowly developing brain damage and your body has started to devour its own muscles because you can’t metabolize food very well at that altitude.
The last part of Everest isn’t even that steep. The worst part has ladders lashed to the rock. I’m not in great shape but I bet at sea level I could cover that terrain in an hour or two. On Everest it takes people in top condition 12 hours. Then you have to factor in the cold, the wind, walking along narrow ridges where a misstep means you fall a mile down the side of the mountain. Doing all that, at that level of exhaustion, while dragging or carrying somebody is going to be impossible for all but the very best climbers, and even they are going to be limited in what they can do.
That said, I’d rescue the guy. I say this with near certainty because the OP said he’s at the start of the death zone, which is 26,000.’
Camp 4 is at 25,900’. 
If I can’t manage that then this guy just saved my life because there’s no way I was going to make it to the top and back.
While it’s true that rescue from Everest in the Death Zone is difficult in the extreme, there isn’t much excuse for passing him on the ascent rather than the descent. On a descent, I can see not having sufficient energy or oxygen to render assistance without needing aid yourself – not so much on ascent, since clearly you have those things to make your summit bid. Prioritizing summitting over a human life is pretty despicable stuff.
I’d leave them and forge ahead.
Because I cannot imagine the circumstances, where I, personally, would have the slightest desire to climb Everest. The thought processes of those who risk their lives for such a goal is foreign to me. Not that I don’t understand it, I just don’t agree with it. So the person wearing my flesh would be so different from the person writing this post, and has given up so much of what’s important to me in life, that I’d assume he’d be willing to write off a complete stranger to reach his goal as well.
Under the proposed terms I would indeed assist to save lives.
I have a nearby lake with water running through it. It freezes in some winters and people venture out to fish and exercise. I’d try to save somebody there too, but I sincerely hope it never comes to that. In the Everest situation I could see making a pact with all climbers that nobody should hinder another climber and would be required to decline help that was not quid pro quo. I can say with confidence that I could hold up my end and decline all help. I can’t say that I could walk away from someone else who needed help.
Sure, but you see that is not the scenario. The scenario is that you are ascending, not descending. Certainly if you are descending and you are struggling as it is, then likely the best choice is to continue onwards, and summon help. Stopping may mean both of your deaths. But continuing to ascend is completely a jerkward thing to do. You can’t possibly claim you kept climbing UP to save your own ass. True, it’s unlikely that a regular climber could do much to help, but there are Sherpas and trained rescue experts, and so thus stopping your ascent and going back for help can never hurt- and can possibly help.
Eta: what fluiddruid sez.
My comments didn’t assume that I was descending. I’m saying that whether you are ascending or descending, these are very difficult conditions to survive in on your own, and trying to save someone else can get you killed.
True, but pretty much by definition, when ascending you’re after a trophy, while it is quite possible that during a descent you’re trying to survive. In any case, even if you can’t personally lent aid, you going back could hasten a rescue by 12 hours or more. There’s no reason not to at least turn back and summon professional help.
By the way, do a google image search for Everest bodies. It’s disturbing.
I’d absolutely attempt to rescue the guy. If I’m going to do something stupid and dangerous, I’m going to do it to save a life, not to get a trophy.
I don’t see why you’d assume he’s automatically unsaveable. If he is not to far away from a camp, it could be possible to give him some supplies to hold him over, go back to camp, and rally a few fresh people (who can take extra supplies because they know they are not going all the way to the summit) to mount a rescue operation.
There’s no such thing as professional help up there, it’s pretty much whoever is in good enough shape to not be a severe danger to themselves and others, and who has enough spare oxygen lying around. Besides, most folks are on radio so letting people know about a problem isn’t a big issue. Doing something about the problem is much more difficult.
On smaller mountains it’s one thing to forgo your attempt; there’s always time for another attempt. Everest (and other 8000 meter peaks) aren’t really like that. A friend who climbed Everest last year and finished her 7 Summits quest had basically exhausted her financial resources. Another attempt for her wasn’t really feasible and she’d been working on this goal for pretty much 5 years straight. Using the hypothetical where you know that your efforts will save a life without putting yours at risk makes the decision much easier than the reality of what happens up there where you don’t know that giving up your life’s goal may end up in disaster. I’d still probably try but I’m not the kind of person motivated enough to pursue the goal of climbing Everest.
It’s interesting to contrast the Sharp case with the Lincoln Hall case, where ascending climbers did stop and help. Given his survival and that of Beck Weathers I would hope that I would try to render all appropriate assistance. I would hope that I would stop short of continuing the ascent and at the very least try to get additional help.
Not to fight the hypothetical, but they do have radios.
My impression is that if someone can’t walk at least somewhat under their own power, there’s no way to get them off the mountain. They don’t leave corpses up there because they’re cold hearted, they leave them because there’s no way to get them down without massive risk to life and limb. If I remember correctly, the cleanup crews that are trying to pick up the litter on Everest are doing it ten pounds at a time. That’s all the more they can carry. Carrying or even trying to drag another climber is right out.
David Sharp was unconscious when he was found. Apparently some of the climbers who passed him thought that he was already dead. It’s obviously pretty shameful that it happened, but it’s also not clear whether a rescue would have been possible at all. This article says that someone was planning to return to bury his body - there’s no way to get it off the mountain.
Lincolon Hall survived a similar situation mostly because he was in much better shape than David (conscious and talking) and was able to walk at least part of the way. He was also below the second step, which is the hardest part of the climb. It still took a team of twelve Sherpas plus the four climbers that found him to get him back down.
No brainer. I try and help.
So let me get this straight. I’m ascending Mt. Everest thinking “… What the heck am I doing here!? It’s freezing! …” looking for any excuse to turn back when…
Eh. Either way, I’d turn back.
The Lincoln Hall situation seems to be one that is closest in spirit to the OP. I don’t think it is the no brainer that many here think. Add in a few more factors:
1/ what if there is not going to be any other chance for you to climb Everest? You’re getting old, you have limited funds, it’s the end of the season for that year and you can never come back?
2/ what if the other climber is in trouble somewhat as a result of their own fault? Not fit enough, not carrying appropriate supplies, pushed themselves when they really should have known to give up?
3/ what duty do you owe to someone in that situation when they decided to do something extremely dangerous, without your backup? You suddenly have to drop everything to provide that backup even though, had the situation been only very slightly different, you wouldn’t have been there at all and no one (least of all the guy you are rescuing) would have suggested you should have been.
4/ what if your own philosophy is that if you get in trouble, that is on your own head and you would be embarrassed if anyone wrecked their own chances by helping you?
I guess perhaps overall you could look at it like this: generally we all engage in a range of activities and we could view it as something of an unstated mutual obligation to help each other if anything goes wrong. But what if someone engages in something monstrously dangerous with full knowledge of the risks, well outside the usual range of what we all tend to do? Does the same social contract apply?
I would be interested in what those with experience of extreme mountaineering have to say. Is it the general culture that everyone pitches in to help if anyone gets in trouble or is it the general culture that expeditions are supposed to be self reliant and do not expect to give or receive help? Perhaps there is no consensus.
I don’t have any answers but I don’t think it is as simple as others state. Which is one of the many reasons why I don’t plan on climbing Everest and putting myself into the dilemma any time soon.