The one that makes it trivial to carry over local patches is Gentoo. I carry a set of patches to every new computer and update them whenever neccesary. No overlay yet :P
I've never had a Nix user actually able to explain why they use it in a way that coherently makes sense because it's a cult. You buy into it before know anything about it.
On many operating systems you keep accumulating junk around your system which become ever harder to clean up. Many techy people re-install their system every few years to clean it up, many non-techy people simply watch their system become ever slower and filled with cruft until they end up buying a new device.
This is the main issue NixOS solves for me. I don't have systemd units or cronjobs or random config files spread across the system. I have one config file/directory, which contains everything.
You're overstating the problem to the point I have more doubts than before I read your argument.
My beef with nix is the arcane syntax to get anything done. Yes, it's documented. No, it doesn't help that it reads like one of those strict, convoluted standards written by a committee of experts.
