Is the classic one actually going to be able to leverage tail-call elimination? Obviously it could be refactored to make a tail-recursive call, but correct me i

Is the classic one actually going to be able to leverage tail-call elimination? Obviously it could be refactored to make a tail-recursive call, but correct me if I'm wrong, it wouldn't be automatic. After refactoring it, the tail-recursive version would be a bit harder to read than the naive implementation. In a sense the Clojure code is in the same boat, it's just that the optimizations are more complicated, because it's not working with singly linked lists in the "address register" and "decrement register".