On Mon, 2021-04-12 at 19:52 -0700, Guido van Rossum wrote:

Why not submit a PR that adds caching to get_type_hints(), rather than promote a paradigm shift?

A couple of reasons:

1. In reviewing the code, I didn't find an obvious way to store cached values. Anything but a non-trivial change would suggest the need for a PEP of its own to document new behavior.

2. I've been hoping that PEP 649 would be adopted, making such a hack or any plan to cache type hints moot.