Lack of bindings is a big problem with Qt that often gets ignored. Generally speaking people don’t want to write C++, even if Qt is nicer than average for writing UI with.
In theory it should be possible to use TypeScript or ClojureScript on top of QML. It's beyond my knowledge if this is enough to write applications. A few people have done some work in this regard, but none of the projects really took off:
I haven’t played with QML in quite some time but recall it being rather bare-bones compared to Qt Widgets, GTK, AppKit, etc and it felt a lot more mobile-oriented than any of those. I think any alternative to Qt Widgets or GTK is going to need to be more “batteries included”, with a wide variety of highly capable widgets ready to use out of the box.