Your analogy would've made sense if Nix had a few dozen implementations to choose from, all being similar in scope and none being definitively better. These are

Your analogy would've made sense if Nix had a few dozen implementations to choose from, all being similar in scope and none being definitively better. These are tools that build upon Nix. The whole point of a language is to have tools that build upon it. It's nothing line the Python -env situation where the sole purpose is to mitigate a design flaw in packaging.