Another thing is, that despite Genera having been gone from the real world for over 30 years, it is still nonfree, and most of the interesting software that ran on it hasn't been publically archived either. That has made it essentially worthless to most people who would otherwise be interested in it. On the contrary, the MIT Lisp Machine system from which Genera was derived is completely free, as well as the LMI system which was another derivative. And there are a small handful of enthusiasts who continue to use, share and improve them.