I am wondering if this is really a problem? I just parallelized some numerical code and instead of threads (Gil problem), I use processes. As far as I understand the only drawback would be that the parallel items cannot share memory, well do you do that? I find it hard to reason about correctness in these cases.

This works a bit. But sometimes sharing memory is useful. Sometimes you may want to parallelise a local function, or a callable class instance - except you can't.

And when I say, "it works", that's clearly on Linux and Mac. On Windows multiprocessing is very severely stunted by lack of forking.

Meanwhile, probably even my watch supports threads.