Most startups that YC has funded that became successful (Series B or higher) were written in Python or Ruby. Now you can say that this is a tradeoff for post Series B, and for that I don't know. I've never worked on a massive Python mono-repo for a company that size. But I know what I've done in Python and, yes, it includes performance optimization in Numpy / Scipy / Cython, and other than Ruby, no other language comes close to the developer performance I see with Python and the ecosystem around it.
That said, there is a good and a bad way of writing Python. You absolutely need tests and lots of them since there is no compiler for vanilla Python. Mypy helps a ton too and so do the linters and even Black. Also, get pdb++ and customize it. The tooling helps a lot.
Now I haven't ever written production Rust, but I have for Go and many other languages, and so Rust may be faster, but other than Ruby I haven't seen anything close.