I use GIMP and FreeCAD quite often and find them very powerful programs, but maybe I'm some sort of genius? I think where these programs don't do well is among the crowd who expect to be able to just click around an advanced piece of software and somehow it just works to get things done! For basic apps this is a reasonable expectation, but CAD is not a simple process.

PS: I've still not managed to learn Blender, not put enough hours in, it is a hugely complex beast of a program that basically requires keyboard shortcut use imho. That interface (beautiful as it is) has so many options that even if I know what I'm looking for I can't find it!

Yeah, to use these UIs you gotta think like a programmer.