Back in the Gnome 2 days this wasn’t as much the case. Plus KDE was kind of a mess back then so the main choices were Gnome or XFCE which had fewer features. When Gnome 3 came around the devs switched hard to a much more opinionated approach, leading to Gnome 2 forks like Cinnamon since KDE was still very underpolished. It’s a bit regrettable that all that effort was poured into Gnome forks instead of improving KDE especially considering how great it is now.