Just uh.. build your own thing?

Boom. Maintainer. Easy.

Why would normal people even want to become an unpaid janitor for someone else's stuff?

> Why would normal people even want to become an unpaid janitor for someone else's stuff?

Social validation. Or, to be slightly more generous, sort of a compulsory way to force someone more experienced to provide some mentorship, by compelling them to review your pull requests.