I would say there's been a mass migration from Twitter to Mastodon and from Reddit to Lemmy. The current numbers are still a small fraction of the original services, but the federated services have reached a critical mass where they now offer comparable value. YouTube hasn't been ubiquitous for that long and it's already pretty enshittified. I see a lot of people who are fed up with it and looking for an alternative. The peertube platform is there, I think with more people and content and it'll join the ranks.