> I thought most of the "modernization" in lisp was done in descendant languages

One core feature of any Lisp dialect is that you can extend the language using Lisp.

Thus, you don't need to "change" the language spec or write a new compiler to extend (and thus modernize) the language.

I'm not sure there's anything now that 'LISP' could refer to beyond the family of languages, of which Clojure, Common Lisp, and even Scheme are all 'modern' dialects.