> It's neat to see how this tends to affect the quality of the software.

In which direction? I’ve used both recently and while I prefer the design decisions of KDE/plasma over those made by GNOME3 in almost every case, I definitely noticed more bugs in KDE. I had frozen copies of my mouse cursor left behind when I moved between monitors quickly, for example. Frankly it’s hard to imagine seeing that kind of instantly obvious bug in a stable GNOME build.

I guess by quality I was thinking size of feature set. It feels more feature complete, I guess? I noticed display bugs in KDE with Wayland earlier this year too but it sounds like that is cleaning up quickly.

Regardless of the DE preference I believe the Gtk/GObject/GLib ecosystem is quite well designed and it's relatively easy to reason around and get into developing with even without using C since there's a ton of available bindings. KDE development is tied to the Qt framework which is essentially C++ only (with Python bindings for the Qt libs). The language is based on pragmatic requirements and I can't see any correlation to the quality of the software.