Why can't tail calls be optimized in JVM-based Lisps?

Question

Main question: I view the most significant application of tail call optimization (TCO) as a translation of a recursive call into a loop (in cases in which the recursive call

Answer 1

There is a reason why the JVM does not support TCO: Why does the JVM still not support tail-call optimization?

However there is a way around this by abusing the heap memory and some trickery explained in the A First-Order One-Pass CPS Transformation paper; it is implemented in Clojure by Chris Frisz and Daniel P. Friedman (see clojure-tco).

Now Rich Hickey could have chosen to do such an optimization by default, Scala does this at some points. Instead he chose to rely on the end user to specify the cases where they can be optimized by Clojure with the trampoline or loop-recur constructs. The decision has been explained here: https://groups.google.com/d/msg/clojure/4bSdsbperNE/tXdcmbiv4g0J