Nothing is stopping the users of those Linux distributions from grabbing the source code and dependencies and compiling any program not in their package reposit

Nothing is stopping the users of those Linux distributions from grabbing the source code and dependencies and compiling any program not in their package repository, or from grabbing a different package manager like pkgsrc, and many proprietary Linux programs that are tied to a particular distro e.g. Steam have been shown to work on other distros with minimal effort. And in regards to the BSDs, what exactly are you referring to? If it's Wayland, that's being ported. If it's KMS drivers, Intel has been ported and radeon is in the process. Nouveau probably won't be ported due to the fact that they already have a pretty stable binary Nvidia driver. The only two things I can think of that aren't compatible with BSD have both been designed with exclusively Linux by the developers heading those projects, SystemD and ALSA, and even then the BSDs already have suitable substitutions with those, init and OSS. So, since there's greater cross-compatibility than ever before, how would you suppose that another nix war would erupt?