Production quality will drop, sure. But how youtube spent years in the beginning was from just people wanting to help, people wanting to share stuff, and people wanting some attention, and there’s still massive amounts of those people making videos. A lot more than the people just after hoping to get paid. Then, of course, even most of the people getting paid would do just fine. They’d just operate like Gamers Nexus and actually speak their ads and sell some merchandise. “This video is brought to you by …”
Platform paying you or not, there’s still a lot of money to be made if you get popular.