The problem is that communities need well, a community to work. People. Just creating the community-name does not solve that. Libre Office enthusiasts could already have been discussing their stuff and posting news in !technology@lemmy.world, !opensource@lemmy.ml or !techsupport@lemmy.world. But they hardly do that.

It is usually best to have few general communities that can branch off into more specialised ones if their topic is big enough. Otherwise you end up with tons of empty communities nobody joins because of a lack of engagement.