I’ve noticed a few communities where the mods haven’t ever contributed to the community (and its dead), or / and haven’t even posted anything to lemmy in years (and likely haven't even logged in for years either) .

Just a FYI, you can ask Lemmy World admins to takeover ownership of communities community and actively moderate it, to help revive it

It seems there were a few people who simply grabbed the community names when Lemmy grew, and had no plans to contribute to them.

Some of the communities that were affected , I’ve seen have a lot of potential (like some of the larger linux distros). Some of those communities even have regular contributors (who may not have even realised yet that the mods disappeared years ago).