In a way, we are going back to how the internet used to be. We started with things like Usenet and email discussion lists. Discussions were federated via email and you did not have to log into any particular website. Anyone with an email address could participate, and admins moderated the groups individually.
Fast forward to today, and we have things like Hubzilla, Mastodon, and ActivityPub. And anyone can participate by creating a federated social media account, and admins of each instance moderate their own instance. Just like the old days, except with better technology.
So, in a way, we have gone full circle. Younger people may not remember the days before Facebook, Twitter, Friendster, Google Plus, Vine, etc., but some of us do. As long as these networks federate, I think decentralized social media will be just fine.