Nix is still trying to be a thing that replaces other build tools. The generated nix file is a recipe for doing what “npm publish” does when it builds a tgz. Every single language has a different way of doing this, and will require its own *2nix to be maintained alongside changes to eg package.json, Cargo.toml, Package.swift. The 2nix bit is the hard part; every package manager has to be re-implemented.
Docker does not have this problem at all. Every build tool on earth works with it, with zero configuration.
Compile_commands.json may have similar output to node2nix etc, but it infects nothing, replaces nothing. It works with all the different makefile alternatives with no additional effort. The closest similarity is with Docker: Docker builders intercept at the file system layer, covering every build system ever; compile_commands at the standard GCC-compatible shell arguments layer, covering ~all C build systems and compilers. Nix does not intercept anywhere, it asks you to use a new tool to do everything from scratch in a Nix-compatible way, covering no build systems.
That’s not to say it isn’t great when you have already built a Nixified package manager replacement for your specific language ecosystem. But it’s not going to take over the world like Docker and compile_commands did. Imploring people to give it a shot is the only way, unfortunately. I will remain open to it, especially if someone can figure out a force-multiplier for these 2nix implementations.