It is heavily used in some industries, just not the average desktop or mobile markets.
By the way, you can compile almost all FreeBSD packages with a bit of care and get a full desktop running on QNX. QtCreator, Firefox, even VSCode can be made running native on QNX (not that anybody would be interested in it though...)
Behind some (unfortunately closed) doors there are almost 8000(sic) packages that run on 7.1. But that was after some time just grunt work and the interesting stuff actually happens below the kernel, not above ;).
Below the kernel is the hardware. QNX is a nanokernel in which the kernel itself is just a tiny executive and all the real work is done in userspace processes, including process management. Pid 1 is procnto, the usespace process manager, and everything else including drivers are userspace processes started and managed by pid 1.
In short, all the interesting stuff actually happens above the kernel, not below. The kernel just does some grunt work of VMM and IPC.
Well. Yes but not exclusively (I am working with QNX since many years), what I meant are the drivers or how resource managers do their job and for which hardware.
Ah, I understand what you said reading it again. You are right, that is "beneath the kernel" not "below".
By the way, you can compile almost all FreeBSD packages with a bit of care and get a full desktop running on QNX. QtCreator, Firefox, even VSCode can be made running native on QNX (not that anybody would be interested in it though...)