Earlier quoted context omitted.
Wow, looking at the family tree above - I can't help but think how this has fractured the BSD development community. Unlike Linux, with has a viral license which essentially forces people to work on the same code base - BSD doesn't, which from a technical standpoint causes way more forking and less contributions back to a main tree.
I don't think the situation is that different. Linux being the kernel, there are lots of "Linux distros", some of which are almost as different from each other as FreeBSD and NetBSD. For example, consider the many package managers (deb, rpm, Nix, etc.), init systems (SysV, Upstart, Systemd, etc.), graphical environments, etc. The BSDs have a different philosophy where the kernel and userland go together as one packag…
Now it's not exactly accurate to call this a fork either b/c they do eventually catch up... but still, lots of non-standard kernels out there.