This is a concern regardless of instance and the size of the instance. At least in my mind.

Personally I don’t have too much concern right now but if anything happens that changes that then I’ll just leave.

Bill is paid by using donations through open collective and Patreon:

https://opencollective.com/mastodonworld

https://www.patreon.com/mastodonworld

Which is confirmed in their blog post about Lemmy:

Also I started paying for the Lemmy cloud servers from the mastodon.world funds

https://blog.mastodon.world/

So mastodon.world, calckey.world and lemmy.world are all run by ruud and looking at mastodon.world it states they have 3 admins in total. So 2 besides ruud. And i assume the same group is involved in all of these.

This is just what i managed to figure out before joining lemmy.

Also !lemmyworld@lemmy.world might be a good follow.