Lisp dialects have diverged quite a bit, and it would be a lot of work to bridge the differences to a degree approaching 100%. 90% is easy, but only works for small trivial programs.
I say this, having written a "95%" Common Lisp for Emacs (still a toy), and successfully ran an old Maclisp compiler and assembler in Common Lisp.
Any idea why is it not a thing? Is this level of interop not practical for some reason?