[fock]

I'm not sure how people manage to "foul up" their system python, but you are doing something extremely wrong, when giving random devtools root access to transform a typical (non NixOS and friends) production environment (your workstation!) into a custom development environment.

Given that: are you sure problems arise around pure python-packages (which generally have a well enough forward compatibility), or is the problem with all the cool "machine-code"-embedded packages (which are a lot!)? And yeah, these might indeed break randomly, when installed on different systems of different time-periods. But that's a problem all binary packages have!