Python has a tremendous amount of momentum because it has become so popular outside of the traditional software development world, but other languages are picking away at it, even given that momentum. And while I am in a bubble, like everyone else, in my bubble, and those I talk to in my bubble, all see large a shift away from Python.

Adding stronger typing, like type hints, could reverse that, of course.

The reason not to is performance and reliability. Typing helps with the latter, Python is just bad at the former.