I do love Nix, and I think much more people should use it, but I don't really consider that a good alternative in the context of my original comment.

I'd argue writing a Nix derivation isn't that different from writing a package definition for any one Linux distribution. It solves the distribution problem for people who use that particular distribution/tool, not everyone. Now, Nix can be installed on any distribution, but if I was going for widespread adoption, I might point to Nix being a solution, but I probably wouldn't advertise it as the main one.