Gregory's ServerYou may not see another platform like those for a while, but that doesn't mean the people aren't going somewhere. It means they aren't all running to a monolithic platform.
I've realized that all I really need is a combination of Discord, Forums, & Mastodon. It's really not different from when I was a kid.
AIM/ICQ for instant messaging
Chatrooms/Forums for more nuanced discussions based on topic.
Livejournal/Myspace/Friendster for keeping up with our friends.