As others have pointed out, this is wrong. You generally by default use shared versions of whatever your system libraries are, which are packaged as part of a g

As others have pointed out, this is wrong. You generally by default use shared versions of whatever your system libraries are, which are packaged as part of a given nix release. Software can specify other, particular versions if needed. If you need access to the shared libs or some special libs in a dev environment you can specify that in the dev environment definition, and they are then available as usual. We use this, for example, so rust libraries can compile against the standard SSL library that comes with nixpkgs.