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.
You know it's excuses, not arguments, because they ignore these considerations when implementing other features.
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