> NetBSD can build the whole OS from source tree to distribution media with a single command. This one, at least, can be done in NixOS/Guix once you check out

> NetBSD can build the whole OS from source tree to distribution media with a single command. This one, at least, can be done in NixOS/Guix once you check out the source -- and the Nix package manager can technically be installed on any Linux distro, too (and some other ports to Cygwin/FreeBSD/Mac etc) and run a single command to get the ISO, or any kind of build product you want. The carefully tested and maintained portability/cross-compilation is another thing though: NetBSD has fantastic support here that is not easily replicated without just doing a ton of work. So its universal basically-always-works cross compilation, everywhere -- is rather unique here. You can't build NixOS ISOs natively e.g. Nix-on-Darwin, which is rather unfortunate.