It occurred to me after my millionth load of laundry that a lift and drop transfer from the washer to dryer would be easier than lift and stoop and toss. So why not?
Hard to tumble sideways?
Anyhow, I have a newish LG dryer with a door in front which opens both from the top and the side, so it is close to being a top loader. I load it from the top and unload it from the side.
Because they work by lifting the clothes up and dumping them down to separate them and allow the flow of drying air to get between the layers of fabric. A top loading dryer would result in the clothes sitting in a wet clump at the bottom of the drum. I guess you could design a horizontal drum that could be top loaded but that would be a lot of complexity for a very minimal gain in convenience.
I used to have an old washing machine with a drum that rotated on a horizontal axis, but was loaded from the top - you had to lift the lid, rotate the drum to the right place by hand, and open a hatch in the side wall of the drum - this is not the exact model, but it was like this: Washing machine - Wikipedia
It was not really even convenient, and the moving parts of the hatch eventually failed.
Wow. That really sounds like a dumb design.
It isn’t, really. The big plus of a top loader v front loader is that the drum is fixed on both ends of the axle instead of just the one in the back. That’s what makes it more stable and less prone to breaking down. My grandma used to have one, as dit my FIL.
https://images.app.goo.gl/s9h87JarxmZ8umzG7
Someone please invent a gyroscopic spinning top loading dryer and give me a cut of the proceeds.
There’s such a thing as a “laundry extractor,” which spins at a high rate of speed, and removes much of the water from clothes. It doesn’t fully dry the clothes, but it reduces how much time they need to spend in the dryer.
https://www.amazon.com/Panda-PANSP23B-Swimsuits-Laundry-Extractor/dp/B08375XS5G
A public swimming pool I used to visit had one of these for swimwear.
You put your items in and press down on the lid and it’d spin them very fast. You’d see all the water drain out the bottom and when the water stopped you knew it was done. The machine was very effective.
Wow, that thing looks like an industrial-strength salad spinner.
To the OP, consider using front-loaders for both machines. Then you can sit comfortably on a small stool while you transfer the clothing from one machine to the other–no stooping needed.
I’ve seen larger extractors in a couple of laundromats, and that’s pretty much exactly what they are. 
My washing machine has an unusually high RPM spin cycle (they claim 1600 RPM, fastest commercial washer speed). I am always amazed at how dry things are when I remove the laundry to put it in the dryer.
Unless I have an unbalanced load (which happens with things like towels sometimes). Then the washer says no way to the spin cycle (for good reason) and I have sopping wet items to deal with.
Nah, Miele offered 1800 rpm in 1999 already. I have heard rumours of 2000. Not 3200, though.
Mine is a Miele. They tell me it is 1600 RPM. Maybe they did faster before and slowed it down. But, 1600 is pretty fast…wait for it till around 2:30. (that’s a different model than mine but close enough).
We have a top loading dryer. I am really not sure how it works. If you look down from the top, it appears to have a half drum and my wife says that rotates. I don’t see how it prevents stuff from getting caught underneath the half drum when it comes around, but they must have some clever engineering to prevent it. There is a bar about 5/8 of the way round (that is a little way past the bottom of) the half drum and maybe that just flings the laundry up in the air. The brand is Fisher & Paykel.
I just googled them and discovered that they are not now selling a top loading dryer (at least in Canada). Even more surprising, they are not selling a top loading washing machine. We have one of each.
IIRC top loading washing machines are water hogs compared to front loading washers (top loaders need to fill the basin…front loaders only need a pool of water at the bottom to slosh things through).
Dunno if it was a law or not though that made that happen (or just general consumer sentiment).
My understanding is that this is true (and front-loaders beat the clothes up less, as well), but that front-loaders also are more likely to require maintenance around the door seal, and develop mildew/stink there if not cleaned regularly.
I do not know about the front seal but it makes sense since it needs to be much more reliable.
Mildew/stink is definitely a thing. They tend to leave pools of water at the bottom which can get gross. Mine has a cleaning cycle to deal with this and, so far (three years) no problem. But I am pretty scrupulous about it.
It also has a hair trap which is nasty to clean.
This is what makes me leery of front loading washers. It seems rather unnatural. We relatively recently replaced our dinosaur of a top loading washer for a high efficiency top loader.
Don’t front loading washers usually sit up higher on a pedestal so there’s less bending down? It seems that conventional front load dryers should also be built higher to the same advantage.