I'll be honest, that does not sound "easy".

It is straightforward, but so is the NixOS module system, and I could describe writing a custom module the same way you described custom Docker images.

It isn't the absolutely easiest process.

But it works on Ubuntu, it works on Debian, it works on Mac, it works on Windows, it works on a lot of things other than a Nix install.

And I have to know Docker for work anyhow. I don't have to know Nix for anything else.

You can't win on "it's net easier in Nix" than anywhere else, and a lot of us are pretty used to "it's just one line" and know exactly what that means when that one line isn't quite what we need or want. Maybe it easier after a rather large up-front investment into Nix, but I've got dozens of technologies asking me for large up-front investments.

This is a familiarity problem. I've never used NixOS and all your posts telling me how simple it is sounds like super daunting challenges to me versus just updating a Dockerfile or a one liner in compose that I am already familiar with, I suspect its the inverse for you.

If that’s not easy I don’t know what is.