Stupid Question About Newsgroups

There are a fair number of rec.aviation.* newsgroups (like announce,
answers, questions, etc.) that have never had a single post as long as I've
been around the 'net. In the first place, why don't they just go away? In
the second place, it would be nice to have a couple of specialized
newsgroups for "hot" topics like maintenance, avionics, and a few others.
Why can't the unused newsgroup name be changed to reflect the needs of the
residents of these ngs?

Jim