People generally aren’t rolling their own matmuls or joins or whatever in production code. There are tons of tools like Numba, Jax, Triton, etc that you can use to write very fast code for new, novel, and unsolved problems. The idea that “if you need fast code, don’t write Python” has been totally obsolete for over a decade.

Yes, that's what I said.

If you are writing performance sensitive code that is not covered by a popular Python library, don't do it unless you are a megacorp that can put a team to write and maintain a library.