Translation layer. There ought to be a thick, fat, slow layer between Fast Python and CPython.

You can write fast native you. You can write fast code by calling into native. The two rarely cross.

If we were clever, we could even have one front-end and multiple backends to go into fast Python, CPython, Cython, embedded micropython, etc. If we were double-plus-clever, we'd add GPGPU, multicore, and compute cluster to the mix.

We'd need someone with deep pockets and high risk tolerance to pull it off. It's a big change. Big changes often fail. Still, when I look at the amount of Python at Google... Well, it'd sure be a pity if all of that became legacy code when we all jumped ship to Julia.