I never said that python is a bad language. In fact it is my favorite language and I probably have written more python code than any other language.
That has nothing to do with it being slow though. And as I said, all those machine learning code rely on numpy (which relies on LAPACK which is not written in python) or highly optimized cuda kernels (which again is not written in python).
Which is the optimal split! Write application/composing code in Python and highly performance sensitive parts in some FFI language (nowadays probably Rust?). It's not great if you do performance sensitive stuff all the time, but amazing if you just want to build something.
I understand and somehow agree with your point, however, it would also be nice for someone to have the ability to build something performant with a language like Python. But this is not really possible today, so the narrative that Python is for prototyping will keep holding.
That has nothing to do with it being slow though. And as I said, all those machine learning code rely on numpy (which relies on LAPACK which is not written in python) or highly optimized cuda kernels (which again is not written in python).