Sadly though, the evidence thus far is that this hasn't happened yet. Some people have felt so strongly about this shortcoming, that they've opted out of GNOME completely and are using alternative desktop environments.
Lightweight desktops as safe harbor
When the news came in that Debian was dropping GNOME, it became clear that GNOME might not be considered a safe choice for a default desktop environment any longer. Xfce, as it turns out, is the new default option for Debian users.
This combined with Ubuntu using Unity (based on the GNOME Shell), Linux Mint opting for Cinnamon/MATE for their mainstream edition, and suddenly the outlook for the GNOME desktop begins to look pretty ugly.
At this time, there are still some distributions that are using GNOME 3 as their goto desktop solution. However, this is expected to change. With the GNOME project set to attempt to completely retool itself, despite losing its core vision of simplicity, I think GNOME could be in real trouble. Not because people will stop using it, rather because their desktop lacks any kind of real vision for the future.
Lessons from Unity
When the Unity desktop came out, myself, among countless others, despised it. The desktop was clunky and the support systems needed to tweak it to meet with our personal needs simply wasn't there just yet. But even back when it was first released, bugs and all, it had a clear vision: To make a Linux desktop environment that was clean, attractive and simple to use.
So even though there is still much debate among Linux users as to whether or not this has been successful, Unity has become a fairly popular option. This is obvious based on the continued growth of its user base on Ubuntu, and its adoption on other distributions as well.
Unity as a GNOME replacement
Is GNOME 3 destined to become a failure and will Unity be the new goto KDE alternative?
The short answer is no. The longer answer goes back to what I said previously: newbies will use the default desktop provided for them.
Advanced users will seek out alternatives and find the desktop that's best suited for them. That said, I suspect that most people who are disliking Unity will not find GNOME 3 to be a logical alternative. The reason being that they both share radical approaches to how they allow the user to browse around the desktop.
Despite the landslide of articles out there expressing how GNOME is dying and why everyone is jumping ship, I tend to take a more agnostic view of the situation. As someone who has been in the GNOME camp for years, I believe a wait and see approach is going to be the most pragmatic in this case.
Even if GNOME 3 is the future of the GNOME desktop and everyone does decide to jump ship, these types of events have a way of working themselves out. Remember what transpired with Unity? Despite the fact that many purists still hate it, other users (such as myself), have come around.
With a little tender loving care, a clearer direction and less focus on overcompensating, I think we could actually see the GNOME project bounce back. Remember, this is a project that has pushed through 15 years worth of challenges. So it's entirely possible, despite the really lousy direction being taken currently, that GNOME releases in the future could be fantastic.