Yes, many communities have these kinds of fuck ups. In the best case scenarios you have a new community half the size and with its attention split. The newcomers still get split between the schism after it happened. The result is multiple weaker communities.
And it take a really monumental fuck up to even get this low level of user action.
Look at reddit, the admins fucked over absolutely everyone and they’ve made it clear they’re only starting. Look how hard it is to get people to come over.
While on the other hand, if most users go to /c/books and by default they see every /c/books on every federated server, then the problem is sidestepped entirely.
No single mod team can get a stranglehold on a community.
Each user gets to choose, by applying or subscribing to a blacklist/while of users or servers. Or they can raw dog it with the click of a button.
But if most users who go to /c/books end up on the “one big /c/books instance” then every other /c/books community except the biggest one, will be a desert that is not worth your time to post to.