Are the available FOSS cross-platform frameworks really not that good?

There's at least Qt, GTK, umm, and, I guess Juce and wxWindows, right? Oh, I see there are more:

https://en.wikipedia.org/wiki/List_of_platform-independent_G...

Can you explain what's deficient about the first two I mentioned?

> Qt

Arcane build system. I mean, I guess it technically supports CMake these days, but I have never been able to get anyone else's Qt project to build without much gnashing of teeth.

Emulated native widgets try for pixel-perfect, but tend to feel wrong somehow.

> Gtk

Outside of a Linux/Gtk native environment, Gtk applications are awful. Take GIMP on macOS, for example: it's had window focus issues (export dialog getting lost behind the main application window) literally ever since Gtk on macOS dropped the XQuartz dependence. And that's the flagship application for the toolkit.

GTK 3 hello world is 150-200mb. They really messed up since GTK 2 was 30mb (like macOS AppKit).