I understand your defederation concerns. That is really what is going to cause problems. Last I checked behaw.org defederated from lemmy.world, that's a genuine cause for concern. However I'm not worried about that long term.

I think Lemmy as a whole was just chilling and then a Reddit Exodus happened. If you owned an ice cream shop and suddenly school is cancelled you're going to freak out a bit.

I think as things settle we're all going to federate again. If we're all alone then all of your initial concerns are completely valid. That isn't to say that defederation is a bad thing. It makes sense sometimes. Even if different instances have different rules we have to share a general set of guidelines not to be a dick. Where that line is drawn is going to be complicated.

Luckily, most people are pretty cool. The loudest are usually assholes, but people as a whole are generally cool.

Decentralized however, that's ok. That's the crux of my argument. A hundred isolated communities isn't going to work (at the current scale) but a few here and there is going to be fine. Shit Reddit did this all the time. Going back to I think one of my first posts I outlined how one community grew from a dissatisfaction from the existing community. The only real difference is that instead of changing from "gaming" to "games" they now change from "[email protected]" to "[email protected]". It's a couple extra characters, it's not a big deal.