So we're missing two things to move this forward:

1. A clear specification (and user-facing explanation) of the behaviour of py.exe in the presence of all possible shebangs and PATH settings
2. Someone willing to update the code

Given the current behaviour is described in PEP 397, step one probably requires a new PEP (unless it turns out to be a single sentence explanation, which so far, it has not). I'd be happy to sponsor such a PEP, but I don't feel the need for it and so I'm not inclined to write it myself.

Also worth noting is that the Microsoft Store package of Python *does* include versioned executables (because we're able to provide them without causing excessive clutter on PATH), but it does not include py.exe (because the versioning of that would get broken really quickly).