If everyone was spread out onto different instances, and communities were based all over the fediverse, the decisions of one instance would be less impactful.
Oh, I wasn't aware that they had defederated from everybody.
Also, doesn't affect me, right? Even if I had a lemmy.world account, it wouldn't affect me because I could simply create an account on another instance, or create my own instance.
Come to think of it, even if they defederate from everybody (as if that's possible), they could still communicate with each other. I'm on several forums that are not part of the fediverse, and they're not dead, so...