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.
Maybe it would be a good idea to put up a request for people to register elsewhere, but honestly, where? Randos naturally gravitate to large servers so if the largest one closes, it gets confusing unless there’s one that is ready as a direct replacement.
People figured out everyone doesn’t need to use the same exact X to have access to the same things X provides many times throughout civilization. Maybe the join page needs to communicate it better, but also people need to try to figure it out.