There's nothing required from PSF to create own repo. I created one myself on S3, all you need is then just update pip.conf to use it. Pip also has functionality to support primary repo and a backup, so they don't need to make their repo a pass through to PyPI, pip basically can be configured to look up first the custom repo and if package is not found then fallback to PyPI.
There's no technical or political obstacle here.
