Those people/use-cases don't care about the GIL. When you're doing anything numerical you're calling into Numpy, Pytorch or Polars anyways and those libraries make use of multiple threads and drop the GIL.
So yes, you can do Matmuls to your heart's content in one python thread and wait for file i/o in another thread without ever running into issues with the GIL. I'd even say if your Python Interpreter isn't bored waiting for stuff to happen, you're doing it wrong.
> Those people/use-cases don't care about the GIL.
This is not true. The primary funding and motivation for the GIL removal work comes from the numerical computing community. The PEP (https://peps.python.org/pep-0703/) contains direct quotes from folks working on numpy, scipy, PyTorch, scikit-learn, etc. and also practitioners from places like Meta, DeepMind and so on, describing the practical constraints that the GIL places on many workloads.
So yes, you can do Matmuls to your heart's content in one python thread and wait for file i/o in another thread without ever running into issues with the GIL. I'd even say if your Python Interpreter isn't bored waiting for stuff to happen, you're doing it wrong.