Earlier quoted context omitted.
Under this abuse of terminology, a pocket calculator is capable of becoming a package/dependency manager. Or any other technology which conceivably could be put to work toward the package management problem, but has not yet been adapted to that need. I concede that these statements are "true", but they fail the relevancy test of communication.
Like I said in another comment, the problem is curating the giant database that maps version numbers to commit refs. Once you pass this roadblock, the tools Nix gives you make dependency resolution a quite a bit simpler problem to solve. The next step is then realizing you actually don't need the useless legacy version numbering scheme at all, and that you wasted that effort for nothing.
I'm not sure what you mean, through, by not needing the actual program versions.