The one thing Clojure is really good at is making excuses. Whatever good or great idea you come up with, backwards-compatible, no downsides, doesn’t matter: be sure they will find a reason not to implement it.
Even Java in its stagnation days was moving faster than Clojure :(
https://ask.clojure.org/index.php/8511/add-digit-separators-support-to-number-literals