AFAIK, QML is now their full strategy for desktop and mobile. QtWidgets is still supported but is considered somewhat legacy I believe. New projects are typically encouraged to use QML I think.
Widgets are still supported (because they work, and they are used by lots of faithful Qt customers), but QML is where they've put pretty much all their development focus since the late 2000s.
New projects are typically encouraged to use QML I think
I wasn't wondering where they were putting their development time.