Just /s/YouTube/Peertube (a federated video host) in your second paragraph, and it turns out to be a thing already:

"What I would like to see instead is a return of self-hosted videos from creators’ own websites plus a site like Peertube that is really just an aggregator of those videos. That way you can also have smaller businesses that provide Peertube-like services for those that don’t want to self-host, but those videos still get included in that aggregator. I think that would be the best ecosystem for competition."