Why should it be bsd's job to port code they didn't write, when gnome can do it for far fewer man-months because they already know what will need porting? If gnome really wants some fancy linux feature, they can ask bsd to implement it. Is there a history of such requests going unserved? I doubt there is even a history of such requests.
Virtually all of the people who write GNOME use Linux; why should they spend any effort porting GNOME to a platform they don't use?
If GNOME really wants some fancy Linux feature, they can ask BSD to implement it.
And the BSD developers don't have the manpower to do that.
Is there a history of such requests going unserved?
See Project Utopia, ALSA, DRM, KMS, cgroups, etc.
BSD and Solaris cannot afford to keep up with Linux. They just can't. So the question is whether Linux people should subsidize OSes that they don't use or just let them fail.