I can pretty definitively say that PyPI will never require you to use GitHub or another provider like that in order to publish to PyPI.
That being said, if there is something we can do to make things better on a common platform/provider like GitHub, we’re certainly not going to preclude that improvement because not everyone wants to use that platform/provider. In cases where that improvement is visible to end users, they may ask for you to support that, the same as they may any other feature request, and it would be up to individual projects to decide if they want to support that feature (and any requirements that feature imposes on them).