I know quite a few Linux users, and not all of them are computer nerds (and none of them use Arch or are part of some small niche group). I'd say about 1/3 of them use Gnome, 1/3 use KDE, and 1/3 use something other than those two.

In general, it seems that those who are used to Windows get along better with KDE.

> KDE should stop assisting with fragmenting Linux

Having a selection of DEs to choose from is not "fragmenting Linux". It's a rather large strength of Linux to be able to select the DE that works best for you. I wish that were possible with Windows!