Everything that's heavily vectorized in the Python ecosystem, including numpy achieves it using optimized backend code written in other languages - fortran in particular. Python is only a thin veneer over those backends. In fact, you're constantly reminded to offload the control flow as much as possible to those backends for the sake of performance, instead of doing things like looping in Python. If that's enough to consider Python to be good in vectorization, I can just link high performance fortran libraries with C, handle non-vector control flow from there and call it a day. I guarantee you that this arrangement will be far more performant than what Python can ever achieve. I have to strongly agree with the other commenter's observation that the memory model is the key to vector performance.

And of course Python has a memory model. While that model is not as well understood as C's model, it is the key to Python's success and popularity as a generic programming language and as a numeric/scientific programming language. Python's memory model unlike C's or Fortran's, isn't designed for high performance. It's designed for rich abstractions, high ergonomics and high interoperability with those performant languages. For most people, the processing time lost executing python code is an acceptable tradeoff for the highly expressive control that Python gives them over the scheduling of lower level operations.