Self-hosting without federation seems a weird trap

Self-hosting without federation seems a weird trap. If you're moving communities, the odds each will end up on the same self-hosted server seems slim. So now you need to manage N accounts for those N servers, and need a client that can likewise be signed into them all.

IRC clients can often do that, and you can go register with NickServ on each, but it's one of IRC's weird, complex warts. And even then, a lot of IRC activity ends up collapsing down to "big" networks like Libera.Chat.

It seems more likely that everyone just moves onto the "default" instance, and what you have is a centralized service that is only *theoretically*, but not practically, self-hostable. It's more technically possible to fork/resurrect if something catastrophic happens with the main operator, but you're still largely at their mercy (and any gentle turning of the monetization screw) until then.