>> Who descides why something should or should not be written I Python? Why shouldn't someone who prefers writing in python benefit from using multiple cores?

I did use the words "most things". I'm not saying this is a bad development for Python, or that nobody should use it. But if performance is a top priority, Python is the wrong language and always has been.

I use Python from time to time, it's fun and easy to put certain kinds of things together quickly. But each time I do a project with it, the first thing I ask myself is "is this going to be fast enough?" If not I'll use something else.