I feel that it's the other way: Slackware is going away (it used to be a major important distributive, and not I hardly ever hear about it), while Gnome is a default environment in many distributives.
I have no reason to like Gnome (I switched away from it when Gnome 3 happened and haven't looked back), but for me it seems that it's pretty popular.
So did I; I've heard all the things, how terrible it is, and so on.
Then, few years later I tried it for myself - and it was actually nice. I started to like Gnome 3. Listening to other's opinions without trying it myself was a mistake.
For me, the problem is not that it's terrible (it's not). It is that the the priorities of Gnome developers don't align with mine.
They want an evolving desktop, keeping up with new trends, ideas and hardware.
I want a stable desktop that doesn't change much between versions and doesn't lag on my eeePC.