I'm a little older and I'm baffled by it too. I've spent many hours chilling in a room with friends playing vidya, and the shadow of that experience that is represented by streaming is just so unfulfilling by comparison - I can't even turn on a stream in the background while I do something else, it just gets annoying. I wonder if it's the natural outgrowth of people getting lonelier over time, where kids whose baseline of human interaction is so atomized that they don't have the same hangup as me and can turn on a stream and feel like it's some kind of genuine connection.

I don't want to sound like an old man telling you that your online friends aren't real, but they're definitely in a different category to friends that you can reach out and touch - and people you watch stream are in a category even further removed from that, because you don't even have indirect interaction with them the way you might have with someone in your WoW guild or whatever.