I think streaming video is a different beast, because the market is littered with loss leaders. It's hard for content creators to switch to another platform when the only profitable ones are subscription based (and not competitive).
Even Youtube, for all its users and being part of an existing advertising company, struggles to break even (reportedly).
Video is so mind blowingly huge compared to everything else. A single youtube video can be multiple gb if you view the 4k60fps version. While making an alternative reddit or twitter is relatively trivial server cost wise.
Even Youtube, for all its users and being part of an existing advertising company, struggles to break even (reportedly).