Depends on what you're doing, right?

Let's take video streaming. I have a pretty compressed version of Arrival that's at 2GB and is a 4k movie ~2hrs long (the original file was ~2x the size). To stream that we need to do 2000Mb / (3600s * 2) = 277.8Mb/s. This also doesn't account for any buffering. This is one of my smaller 4k videos and more typical is going to be 3Gb-5Gb (e.g. Oppenheimer vs Children of Men). Arrival is pretty dark and a slow movie so great for compression.

Now, there's probably some trickery going on that can get better savings and you'll see used with things like degrading the quality. You could probably drop this down to 1.5Gb and have no major visual hits or you can do a variable streaming and drop this even more. On many screens you might not notice a huge difference between 1440 and 4k, and depending on the video, maybe even 1080p and 4k[0].

For comparison, I loaded up a 4k YouTube video (which uses vp9 encoding) and monitored the bandwidth. It is very spiky, but frequently jumped between 150kbps and 200Mbps. You could probably do 2 people on this. I think it'd get bogged down with 4 people. And remember, this is all highly variable. Games, downloads, and many other things can greatly impact all this. It also highly depends on the stability of your network connection. You're paying for *UP TO* 300Mbps, not a fixed rate of 300Mbps. Most people want a bit of headroom.

[0] Any person will 100% be able to differentiate 1080p and 4k when head to head, but in the wild? We're just too used to spotty connections and variable resolutions. It also depends on the screen you're viewing from, most importantly the screen size (e.g. phone).

> 2000Mb / (3600s * 2) = 277.8Mb/s

2000Mb / 7200s = 0.278 Mb/s, or 277.8Kb/s

> It is very spiky, but frequently jumped between 150kbps and 200Mbps. […] I think it’d get bogged down with 4 people

That’s just burst buffering as fast as it can, you didn’t capture the average. It doesn’t suggest it would slow down with 4 people. 4K on YouTube takes 20Mbps, so to parent’s point, you’ll have plenty of bandwidth to spare if 4 people do this at the same time on a 300Mbps line.

> I have a pretty compressed version of Arrival that's at 2GB and is a 4k movie ~2hrs long (the original file was ~2x the size). To stream that we need to do 2000Mb / (3600s * 2) = 277.8Mb/s.

Your math is WAY off.

2 gigabytes / 2 hours is only about 2.22 megabits/sec.

Blu-rays don't do anywhere near 277Mb/s.

First, if it was 2GB * 2 for the source of your recompressed copy, that's 4GB * 8 bits per byte = 32 Gigabits (Gb), or 32,000Mb. Two hours in seconds is 60 * 60 * 2 = 7,200 seconds.

32,000 / 7,200 is 4.444Mb/s. Streaming your 2 hour long 4GB movie could be done with ~5Mbit. A 1Gb/s connection could handle streaming ~200 of these movies.

Going back to Blu-rays as a source, an Ultra HD Blu-ray maxes out at 144Mbit but in reality most movies are encoded at a much lower bitrate. Most movies will cap out around 40-50Mbit. You could do 20 of these straight Blu-ray movies on a 1Gb connection.

https://en.wikipedia.org/wiki/Ultra_HD_Blu-ray#Specification...