That's why progress has got so slow the last 6-8 years in so many parts of the OSS world (and on lots of proprietary software, that lazily relies on OSS). Things like Gnome or OpenOffice are essentially the same as they were 10 years ago, whereas the proprietary alternatives have gotten tons of changes.
GTK+, the main toolkit behind Gnome has one (1!) major contributor (which complained about the issue). In a proper world, something like this, used by so many millions, should have at least a full time team of 10 persons.
Contrast the additions to GTK+ in the last 10 years with the development of the corresponding Cocoa libs, and it's like night and day. A tree-view widget here, a spinner there, ...
Small libraries and stuff can still flourish under such an environment, but not big, co-ordinated projects.
But then again, they seem to still be receiving some amount of corporate sponsorship from Red Hat.
A few years back (when Nokia stopped supporting the project) things looked a lot more gloomy: http://wingolog.org/archives/2008/06/07/gnome-in-the-age-of-...
Then again, any desktop environment or toolkit is bound to be somewhat unsexy these days when the focus is on web and mobile.
I also wrote about this back in 2008: http://bergie.iki.fi/blog/gnome_in_decay/