The more serious problem is that with the obsolescence of GTK+, we may end up not having a good standard GUI toolkit to write applications on Linux anymore. There is much focus on graphics lately with the alternatives to X.org being developed, but Linux still doesn't have a good solution to make graphical apps with resolution independence, proper text rendering, fluid layout and good accessibility. Not that other operating systems are being that much better at any of this.
This is already the case in many ways, hence the popularity of web based apps and native applications that run their own webserver to be accessed via localhost. I actually found GTK+ easier to use than Qt, but there is no windows version for GTK3, not even one in sight so it turned out that I was writing a Linux-only program without realising it! GTK3 itself is not too bad to use, it's just a bit limited and needs work.
The Gnome desktop though, is a whole other story, it seems to be controlled by developers who lost the run of themselves and tried the Steve Jobs approach - "We're giving you a UI change and you're going to like it!"
It's later than you think, the joint Russian-American space mission has already begun.