1. Most people who submit videos do it because they enjoy it, not to start a career (or at least it doesn’t begin that way).
2. Most creators at this point have sponsor-spots in their videos. That’s still monetization they control.
3. Donations are a thing. Both to Framasoft (Peertube developers) as well as direct to the creators themselves. This still makes up a large portion of creator income.
4. Personal sales. Lots of creators have their own products these days. Some of them are novel and others are high quality.
5. Affiliate links to product promotions.

Peertube makes it really easy to promote whatever you want in the “support” button.

So really the only thing they’re missing out on is adsense. Which, fuck Google. And is only a small (but not insignificant) portion of their income.