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.
Well Ruud who runs .world also runs Mastodon.world which is a fairly large mastodon instance, so he is somewhat of a known quantity and has experience running large Fediverse servers. His mastodon server has handled a large population and donations happen through Open Collective for transparency as well. He also runs Calckey.world though that is much smaller.
Do you think spez was good once?
Not really. Also by your logic you can’t trust anyone ever because there is always a risk they turn bad at some point in the future. All we can do is evaluate what we have in front of us at the moment. Current evidence suggests Ruud is trustworthy, committed and capable of running a large Fediverse instance.