To support decentralization and spread, should lemmy.world close registration at some point to prevent a performance overload due to too many users? Of course, if registration is disabled, there could be a hint placed somewhere near that from other instances you can interact with content on lemmy.world just like you had registered on it. There could be a link to join-lemmys instance overview.
It makes sense to pause registrations if an instance is actively overloaded, but there’s no reason it can’t keep growing if more hardware is added and the performance issues are resolved.