Clojure is about its rigorous and pragmatic "immutability first" paradigm that you simply don't get from other PLs.

LISP is much more than just a runtime syntax, such as its distinct evaluation model and metalinguistic core.

The JVM was chosen for Clojure because of its reach and vast ecosystem. People have ported Clojure to other runtimes, even Beam (Clojerl), where it enjoys decent success, too.