Gnome is very much alive, the blog entry from a month or so ago was concerning but it's still very much a lively project.
I liken it to XFree86. While it may have been very popular and widely-used at one point, it didn't take long at all for users and developers to flee once things started looking bad.
People just haven't been happy with GNOME 3. That's a fact. And with no improvements visible on the horizon, more and more people are moving to MATE (and a few to Cinnamon).
GNOME can't survive in its current form if people and developers continue to leave it in favor of better desktop environments.