Google/Instagram have done bits, but the company that's done the most serious work on Python performance is actually Oracle. GraalPython is a meaningfully faster JIT (430% faster vs 7% for this JITC!) and most importantly, it can utilize at least some CPython modules.

They test it against the top 500 modules on PyPI and it's currently compatible with about half:

https://www.graalvm.org/python/compatibility/

But investment continues. It has some other neat features too like sandboxing and the ability to make single-binary programs.

The GraalPython guys are working on the HPy effort as well, which is an attempt to give Python a properly specified and engine-neutral extension API.