Any youtuber, myself included, can attest that a majority of youtube views demonstrably don't. A key factor in finding success as a youtuber is getting better at retention, hence all the ridiculousness and MrBeastness: some people specialize in retention, and they do better.
It's weird from the standpoint of someone who sets out to watch an entire thing, but almost nobody sticks around while watching videos. It seems like the mass of youtube viewerdom are bouncing around like mad, all the time.
It's FOMO on a second-by-second basis. No matter what you're watching now you could be watching something better. The UI even somewhat encourages this with the way it displays a list of additional videos below what's playing now.
It's weird from the standpoint of someone who sets out to watch an entire thing, but almost nobody sticks around while watching videos. It seems like the mass of youtube viewerdom are bouncing around like mad, all the time.