Re: Solving problems that do not exist anymore
GTK is pretty well updated on BSD, so I don't think there's much to worry about. While Gnome is questionable on how much uproar would be generated if it were to drop everything but mainstream Linux distros, I very much doubt there would be no one rioting if it were to happen to GTK. It drives too much of desktop *nix to not be available on every platform.
Even if it were to go Linux-only, you already know there would be a fork for it, or at least a replacement.