By that logic you also forgot iced, libcosmic, libxfceui4, kirigami, xapps, flutter, .NET Avalonia, electron/html, sdl/raw rendering, and probably alot more that I don't know or can think of. This really has been just GTK and QT for ages.
I wonder when Gimp will upgrade to GTK 4, and realize GNOME has twisted the GTK framework into a draconian railway to making a mobile app with rounded corners, and give up and switch to Qt like so many other apps have.