Ruby is on its third (I think?) JIT now? I'm a little surprised, given Ruby's reputation as a wacky "anything goes" language with a very complex grammar, and it makes me wonder why that is? Does it have to do with the design of the runtime itself more than the language semantics? Or is it more incidental, e.g. many popular ibs are C wrappers, already generates bytecode files, and so on.
If the Python steering committee isn't willing to do the same, they'll probably won't get a working JIT any time soon. Developing a JIT externally, or even from a branch, is just too hard.