Qt requires a commercial license in this use case. Why bother if Chromium is free and it works?
It's simply that right now, web is the best. Far from perfect, but the best.
Could you go into more detail? With Qt, you can use Qt Designer/Creator and get a working UI pretty fast and easily.
* write once, run everywhere.
* the amount of tools and libraries.
* Modern javascript is better than c++ or python for UI
* the availability of good web developers
* The npm ecosystem is a bit overzealous in the dependency department. Not everything is bloated inside npm or out of it but a lot of it is.
* Javascript itself hasn't changed much in the way of making DOM creation/mutation easier. Custom elements, shadow DOM, etc. were nice but at the end of the day you still need to call createElement a lot and do everything manually. You're probably referring to using libraries, of which some are nice but many suffer the above-mentioned bloat problem. Event handling similarly hasn't changed much.
* True enough, there probably haven't been this many of us in a long long time! More people must mean more good people.