But makes me think we'd be better off if we all just focused on a single one, and grew it, made it better. Not having 4 versions of something almost identical. Fragmentation can hurt adoption.
Personally I prefer lisp 1 languages, like scheme. Even there, though, there was a split over r6rs, so we got a bunch of mostly-like-r5rs schemes and racket.
Maybe the problem is that lisps are no longer popular enough to have a winning implementation! If there is one, though, then it's Common Lisp on SBCL.