Anecdotally, I strongly doubt this is true, although my environment is probably quite biased. I know a ton of people who use Gnome, some who use KDE, and I think roughly all of these people use them with Wayland. The standalone-WM users I know are also mostly on Sway or other Wayland ones. The only real X11 holdouts seem to be people using X11-only DE's, such as Xfce or Cinnamon.