I’m not sure this is the same problem as a community that has gone offline or was scrubbed in some way. A community that’s inactive or not being properly maintained sounds like a different kind of problem. In this case, we mainly just hope that the federative design means such communities eventually get replaced by people who want a better community, possibly on another server entirely.

I can imagine someone writing a bot or script to detect dead communities.

For !askhistorians@lemmy.world , you need actual motivated historians to take over

Not sure we have those on Lemmy yet