I honestly think it's hard for "Nix to Nix" simply because by trying to make everything reproducible, it is dealing with more of upstream's garbage, and "reifying" the hoops that people jump through doing sysadmin things in code looks scary.
I really want more upstream developers to use Nix, so they might loose their myopia, and start thinking of the the FOSS ecosystem as a whole, and not just their own packages within it. Nix is the best way to get the bird's eye view, I am sure. Just try not to gag at what you see!
[1] Though I still maintain that contributing to Nixpkgs is much easier than contributing to e.g. Debian or Fedora.