I do fine on 2 TV’s and also zoom schooling on a 25 mb/s link.
Six internet users here, two people working from home. There are times when four streaming services and two online games are running. 100Mbps has always been plenty.
Comcast recently installed a new router in my dad’s house. I found out about this because he was telling me that his bill went up. To his knowledge they never even asked if two septuagenarians needed 800Mbps. They stream Netflix on one tv and shop on Amazon.
I have 200 megabit and it has never seemed slow, we often have 3 devices streaming at once and my computer downloading things, plus various smartphones doing things as well. No slowdowns at all.
Now what may slow things down is Comcast overselling local capacity, and when everyone gets home from work and starts watching HDTV at once the neighborhood internet can get slow, sometimes very slow. 400 megabit won’t help with that.
If it is big problem for you, one way around it is to sign up for Comcast Business internet. There are a few downsides. It is more expensive for the same speed, and you can’t have residential cable TV and business internet at the same time.
In exchange for those downsides, your speed is guaranteed. My 100Mb is mine. It doesn’t matter how much my neighbors are using, I get my full 100Mb. When I have a problem I call business customer support, which is far, far superior to residential support (from a few years ago, “We see there’s a problem, but we don’t know what’s causing it. You’re lucky you’re on business, because we’ll keep working until it’s fixed. If you were on residential, we’d just close the ticket.”)
Xfinity has gotten much better, IMO. I had been on a 100 Mbps plan for years (no TV/landline), and they were charging me $120/mo, with the price increasing by about a dollar a month (generally in the form of some new fee or tax).
But a couple of years ago they offered a 1 Gbps service for $100/mo, with no fees or taxes, nor was it any short-lived special offer. And they’ve held to that–my bill is precisely $100.00/mo, and has stayed that way for a couple years now. It’s not as good as symmetrical fiber, but I do get >900 Mbps downloads from fast sites.
Some local places are getting AT&T fiber. Not in my exact area yet, but maybe Xfinity is starting to feel the heat from competition.
Anecdotally, that seems to be the biggest thing. In areas with competition (that isn’t satellite) they seem to start offering better values. If you’re in a monopolistic area, it’s all the market will bear…
In my neighborhood, Cox was the only high-bandwidth option, as our phone lines were too old and far from the exchange to allow more than 2.5 Mbits/sec over DSL. For comparison, my MIL’s local loop is less than 30 years old, and gives her plenty of bandwidth for her needs.
About a year before Covid, Cox suddenly started offering cut-rate packages to users who would sign a contract rather than go month-to-month. A little later, utility trucks started going down our alleys and threading new fiber on our poles. CenturyLink had picked our neighborhood for new Gbit fiber service, and I told Cox to go pound sand.
Thanks to the thread getting me all irritated at Xfinity again, it inspired me to spend 94 minutes on hold and escalating with their “customer service” in order to demand a 100 Mbps (up from 80) for $60 per month (down from 85) - the price they give their new customers.
I am exhausted, and hate people, but I have triumphed. Until the next round of rate increases.
Agreed on Comcast Business, but it’s $140+ per month for just Internet where I live, so price may be a concern.
Your post flew instantly to my mind last night, as I was hooking my brand new, fresh from the box, Oculus Quest 2 up to my PC. I fired up Microsoft Flight Simulator 2020, and was greeted with a mandatory, 38 gig update. 
I’ll get to play it tonight…
Haha! Sorry. It’s probably my fault.
Flight Simulator should definitely have the ability to download updates in the background while playing the game.
I have about 100Mbps, and usually there are 3-4 devices streaming with no issues in the house. Last week, we had 3 people playing Borderlands 3 on Stadia (streaming game service; so think streaming movies, but interactive), one on Steam, and at least one person also streaming videos on YouTube simultaneously, with no issues.
Do online games really use a lot of bandwidth? I would have thought it would be positional info (for you and any things you’re shooting), which may seem like a lot, but not compared to an HD video.
Stadia is streamed. Games are run on a remote computer, and the imagery is streamed to your TV.
Prior to the onset of the pandemic, I used to go to the Dairy Queen in the next town over about twice a week for supper. I’d take a laptop with me and sit at the table and work from there for an hour or so each time. Not once did I ever have any problems with speed even though their connection was only 5 Mbps.
At the office, we have a dedicated gigabit link and so we obviously never have problems there. When out on the farm, I don’t even bother with Internet or tv.