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.
Even as a small instance operator, the media storage increases at a pretty steady rate. It’s probably going to be a case of months or even years before it starts getting to costing money I will notice. But, still I guess we can by then start to purge very old stuff if we’re not a big instance though.