The article doesn't mention recent/ongoing improvements to PyPy in the "speed" section, and doesn't mention concurrent.futures in the "asynchronous programming" section. Seems incomplete to me.
You can't say that Python has both speed and great libraries. It has one or the other. Hopefully this will change at some point and I'll be able to reap the benefits of both.
If I have code that wants those libraries, PyPy is not an option. As an end user, I don't care who should fix it. I just know that I can't get my job done with PyPy.
And the authors of numpy, scipy, pandas, etc seem to agree that it would be impractical to rewrite these libraries in the way you are suggesting.