[vbezhenar]

I've read many opinions of those who used QNX on desktop in the past, that it felt much more "snappy" compared to other systems.

Desktop definitely has real time tasks. Any animation is real time task. When I'm listening to music, it's real time task. macOS sound interrupts for a short time, when something hardware-related happens, so it's not pleasant experience. You might argue that user can tolerate those interruptions, but for me those are just bugs.

[vacuity]

Indeed. There are people who have a fair point that desktops for users (as opposed to servers) should have a focus on being responsive and useful. Like how writing on a piece of paper produces meaningful markings in real time, user interfaces should be able to perform tasks with analogous interactivity. See comments about BeOS elsewhere in this thread. I don't know about the extreme, but the overall sentiment is valuable and a far cry from the current state of the desktop experience.