Gnome is slowly going away. Slackware is not packaging Gnome since more than 10 years. The only thing they "produce" is the gtk and guile ecosystem where every new release is incompatible with the old one.
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.
> I switched away from it when Gnome 3 happened and haven't looked back
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.
Most of GNOME development is done by Red-Hat employees, it isn't going away.
KDE and XFCE come in second, and then there is everyone else.
Anyway, it is mostly irrelevant, as most of us use GNU/Linux headless on a server/IoT, containers, or only the Linux kernel alongside Android and ChromeOS userspace.