1) Qt Widgets development stopped with 5.0. I had bugs filed on the embedded Linux targets and was told "sorry, these will never be fixed".

2) #1 means that Qt wants you to use QML. I need to run a Javascript engine on my target? Note in the comments of that blog post that they hope to run on an A7 (or really fast M7)...someday.

2b) ...And if they do run on a lower end platform, you still need a POSIX O/S. uCLinux is not a great option on M3/M4 CPUs and keeping the binding dynamic on those cores to stay LGPL compliant is extremely difficult.

3) QML bindings are a pain in the ass, especially when you're trying to put a UI on legacy code.

4) Most crucial: Qt Lite and QtDC are commercial products only.

So, in my opinion, embedded is still a 2nd class player. Or, I could clarify further: low end embedded is a 2nd class player. If you're working on automotive HMI/IVI? They'd love your business.