Worth mentioning:

• Lemmy itself is an open source software. It’s developed by a community, and was originally created by two developers. It does not make money, except from things like donations or patreon.
• Lemmy instances are run by different members of the community. Various folks have answered ways that instances could make money but may not make money in any ways.

since it’s all federated it’s most likely donations and out of pocket. the real risk here is that as communities become more and more centralized, the cost to operate increases significantly (the lemmy.world guy had to upgrade servers at least twice during the boom). there’s a chance that these instances won’t stay around long term, i’m not sure how the lemmy code base deals with instances dropping off. does everyone lose access to all of those servers? since your account is associated with that instance do you not also lose your account and posts?