Sort of, but e.g. in case of MacOS you'll have some apps that can't be installed as Nix packages and some things that can't be configured in OS

Also was not mentioned, since every dependency is unique you should have no trouble discerning versions that look the same, but in fact configured different or depending themselves on different versions of things, and introducing breakages that way. If you find that some specific configuration of dependency is causing you trouble, you can switch to a different one even if another package depends on this troublesome version.