Nope. All Python programs in Nix are effectively venv'd, so-to-speak. The problem is that if two packages A & B each depend on the same library L but they requ

Nope. All Python programs in Nix are effectively venv'd, so-to-speak. The problem is that if two packages A & B each depend on the same library L but they require different versions of it, any Python code that imports both as libraries will end up with two, potentially incompatible, copies of the same library in its import path. And Python doesn't support this, so it uses the same version of L with all the Python code running in that process. So now depending on whether some package P which requires both A and B imports A first or B first, A will end up using B's version of L or vice-versa. This sometimes does nothing, and it sometimes causes very weird, very subtle breakage. Thus for all of the Python libraries in Nixpkgs to be usable in any combination by any package in Nixpkgs, there can only be one version of each Python library in Nixpkgs. Once your package collection is large enough, you start actually encountering versioning conflicts as described above in the transitive Python dependencies of your end-user application packages. That's why Linux distros run into these integration issues. Application developers generally don't because their applications development environments are much smaller.