Why can't lemmy mods or admins clean up dead communities like askhistorians and others? I know they have a hard job and everything but we need an active user base to make lemmy to thrive.?
What's the question here? Why dont they delete inactive communities? Why dont they hand the keys over to someone else? If a community is dead, posting in it will mean it is no longer inactive at the least. If you want to see activity, make activity.
Nearly all of the search options sort your front page by activity, so removing old communities won't make active ones stand out any more. If you're searching for new communities and fail to notice the last message was 3 years before you posted your 900-page essay, that's on you. Even if you make the background of stagnant communities bright red, there's still going to be someone who complains that they somehow "didn't get any warning".
Retaining old content has value, you wouldn't believe how many answers I've found on 10+ year old reddit posts that have long since been archived. Information is valuable, it should never be removed unless someone is being harmed by it.
I was never sure what triggered reddit's archive of a post. I mean even just this year I had someone send me a reply and I had no idea what they were talking about. Looked up the post, it was over three years old! And when I asked them about it, they said they knew it was old but chose to reply anyway. Some people just have really boring lives I guess.