> Simple package based distros like Arch basically just extract archives. Very few packages trigger post-install steps which usually just (re)generate something like initrd.
Sure it's simple, just like 80% solving the problem is usually significantly simpler than solving it 100%. Nix (and its generation) is the only package manager that actually works.
Try installing kde and gnome, then uninstalling both and check how many packages remain.
Nix can do that with the whole world with nothing residing.
> Try installing kde and gnome, then uninstalling both and check how many packages remain.
Sounds like a package manager or package problem. Competent package managers (e.g. dnf) remove unneeded packages and all their owned files. Albeit, I think with apt you need to do a manual autoremove to remove orphaned packages.
Not suggesting that they're equivalently powerful compared to nix, but this specific thing shouldn't be a problem with traditional package managers.