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.
Probably not. I understand the concern, but another issue is sending people to smaller instances which may end up disappearing. It’s all run by small groups of volunteers or even by individuals, at least on the bigger servers you have, at least in theory, a lower chance of the instance vanishing (with your account).
I don’t know if there are any plans to cooperate between instances for tech support/funding or if accounts can be transfered one day. Until then - a slow lemmy.world feels like the lesser evil.