You might be surprised at how hard it is to get money donated for this sort of thing. Large companies often have their own build infrastructure and thus build things for themselves from scratch, to the point of building their own build toolchains (e.g. look at Google and bazel, Facebook and buck). So the way they handle packaging means how the overall packaging ecosystem functions does not impact them like it does individuals or smaller companies.
This is also why companies only started funding PyPI security work about two years ago; downloading source securely from PyPI is important to big companies as that's where they grab the source that they compile. But funding pip improvements only just happened in Decembe, starting with the new pip resolver work got money (https://pyfound.blogspot.com/2020/03/new-pip-resolver-to-rol...). And all that money came from Mozilla and the Chan Zuckerberg Initiative; two huge non-profits, not companies.
Add on to the fact that the PSF is projected to have a $627,000 USD loss this year due to PyCon US 2020 being cancelled and it makes finding funding really hard (https://pyfound.blogspot.com/2020/03/psfs-projected-2020-fin...).
Python overall very much runs on volunteers, but the packaging system especially. The core team of Python itself might generously have a total of 3 devs/week being paid to work on CPython spread across all contributors (IOW it is nowhere near as impactful as 3 actual full-time devs who aren't context-switching constantly between "work work" and "Python work"). But for Python packaging in general? If you don't count conda I think packaging has less than even 3.
But if anyone wants to donate to try and rectify this, please go to https://psfmember.org/civicrm/contribute/transact?reset=1&id... and donate to the packaging WG!