Having been a former Qt developer, I couldn't disagree more. I have no desire to touch that dumpster fire again. To its credit, it's best in class, but that isn't saying much.
I'm a fairly newer Qt developer so I really only have experience with QT5. Perhaps I was fortunate to miss the growing pains you seem to have endured. For me, the ease of doing cross-platform development along with the ability to create really high quality GUIs with QML made me fall in love.
Qt5 is much nicer, but still a pain. QML is even better, just too coupled to Qt. Unfortunately you have a point that there isn't a better cross-platform native GUI toolkit.