They did! MATE is fairly popular, but as to why it happens I think it's about people.

There are only so many people willing (and able) to do the often difficult and unglamorous programming work that goes into maintaining something like Gnome.

If you're working on a major distro you have a certain level of trust in Gnome 3 because the same people delivered and supported Gnome 2. I'm sure when Gnome 3's direction became clear dozens or hundreds said "no way! I'm going to start my own fork which will never change!"

But how do you know which one to pick?

The sad part is that Gnome 2 had a whole ecosystem of third party software that integrated with it. Just a few of that got ported over to Mate (usually just s/GNOME/MATE/g) but it never gained the same traction.

Why did it need to be ported at all? Shouldn't it "just work"?

Mate had to change all “Gnome” strings to “Mate” so both could be packaged/installed in parallel and probably also for legal reasons.

This means all DBus interfaces need to use the new name, a nautilus plugin must now call caja functions instead and so on.

...huh, well that's frustrating! Could this be solved with a basic compatibility layer?

or decompile, touch strings, then recompile.

Mate gives me a warm feeling of being at home where all is totally understandable and nothing has changed since 10+ years ago when Gnome 2 was a king.

I think that's where the fracturing comes in. For whatever reason, distros will ship with the new thing. The past 2 or 3 places I've worked adopted MATE (a continuation of GNOME 2). And, of course, there was instability at these places in figuring out which direction to go.

> For whatever reason, distros will ship with the new thing.

Chicken and egg problem: Popular distros will follow popular DE's, because they have the most people making their way out of bugs and problems.

MATE, on the other hand, is kinda barren compared to more popular options. Even if it's the same old Gnome2 desktop of yore

> The past 2 or 3 places I've worked adopted MATE (a continuation of GNOME 2).

Oh, so it did happen, I’m not currently a Linux user and had no idea!