Yeah, you can script vim in Lisp (Scheme to be more precise). That's been possible for a long time, with mzscheme. But virtually no one ever does.
The vim ecosystem is overwhelmingly vimscript. Python is gaining popularity, and if anything a mainstream language like that is likely what the neovim ecosystem will eventually wind up consisting of. Not Lisp.
Contrast that with emacs, where it's Lisp, Lisp, Lisp, and will continue to be Lisp for the foreseeable future (with a detour to Scheme possible in the long run).
A fully Lisp ecosystem is one of emacs' greatest attractions, and one that neither vim nor neovim is likely to ever achieve.