If I had to predict the future I’d say that the fediverse will survive, but Lemmy will probably not get any bigger and then slowly get smaller. On the other hand Mastodon is doing pretty well and will probably be the long term survivor and grower of any of these federated sites.
Threads, bluesky, Post and whatever other corporate creation will probably continue to exist, but there may never be a place where almost everyone congregates again. I think that will die with Twitter.