> This is not really accurate. Qt relies on a lower level windowing system (X Window, Wayland, Cocoa, win32 etc. etc.).
Qt also supports rendering directly on the GPU (or with software rendering on the framebuffer) without any windowing system such as X11 or Wayland - that's likely how it is most commonly used in the wild, as that's one of the main way to use it on embedded devices.
Well, yes. I can't tell too much because of NDAs but if you go buy a recent car there is a good chance that all the screens are rendered with Qt on Linux or a RTOS - there is likely more of those than desktop linux users as much as this saddens me
Qt also supports rendering directly on the GPU (or with software rendering on the framebuffer) without any windowing system such as X11 or Wayland - that's likely how it is most commonly used in the wild, as that's one of the main way to use it on embedded devices.