By that last statement, you mean more connection=less resistance kinda thing?
Discussion
With Peertube you stream from an instance, but there's also p2p streaming. So more people watching, more people to stream from. It's like a torrent with 1 seed vs a torrent with thousands of seeds.
Plus, if it becomes popular, there would be more instances, just like there are many bitcoin nodes.
Because it's all running natively, not from a server. That makes sense. Assuming I get you right.
Very short explanation: https://framatube.org/videos/watch/217eefeb-883d-45be-b7fc-a788ad8507d3