My view of where the Unix community is
I've written before about how there once was a time when Sun could be seen as the heart of the Unix community (cf), and this view of Sun's place in the community is why some people don't like Oracle's Sun-related actions (cf the commentator here). As I wrote back then, my feelings about Sun are somewhat more complicated and tangled (cf) because I don't think that Sun has been the heart of the Unix community for a long time.
There's a lot of reasons that Sun stopped being the center of the Unix community (and maybe I'll write about them sometime), but the important thing is that it did not happen this decade or even this century. Sun ceased being the center in the mid 1990s, when it increasingly had only tired hardware and tired software to offer. Even back then, it was not hard to see where the community was going if you paid attention: it was going to x86 systems, because they were good enough and cheap.
(I don't have a clean and clear definition of the Unix community, but to me it is some mixture of the people using Unix, the people enthused about Unix, and the people who are evolving Unix and moving it forward. Mostly the latter two, really; you need to be interested in Unix as itself in order to really be part of the community instead of just a passive user of computing. This is why most of the OS X people don't count.)
Thus it's clear to me that today's Unix community is found in either FreeBSD or Linux. The part of the community that likes Unix as it is has mostly wound up in FreeBSD; the part of the community that has radical dreams for the future has mostly wound up in Linux (this is where it's appropriate to borrow a Henry Spencer quote and say 'those who don't understand Plan 9 are condemned to reinvent it, poorly'). This is not a new development; it's been this way since no later than the late 1990s.
(My somewhat inflammatory view is that while many of the people of the old Unix community who stayed around Unix seem to have wound up in the *BSDs, the spirit of the Unix community mostly settled in Linux. Unfortunately there are significant drawbacks to this split, some of which I have captured in my borrowed witticism.)
Sun's death and absorption by Oracle was not a real loss for the Unix community because Sun hasn't been important to the real Unix community for some time. The real Unix community is going on just as it has been for years, and is probably roughly as healthy as it ever has been.
Sidebar: why the Unix community is not in all of the *BSDs
OpenBSD is not where the Unix community is today because its scope is too small, although valuable. NetBSD and DragonFly are simply too small, period. Only FreeBSD is large and encompassing enough.