Which of the small operating systems is more promising?

Question

Operating Systems

Everything that is not Win, not Mac, not Unix (Linux, BSD, Solaris). Things like Haiku OS, Kolibri, Visopsys, Dmitry Zavalishin's Phantom.

Answer 1

The listed operating systems have no real prospects. If you are interested in operating systems other than Unix/Linux, welcome to the world of RTOS. There are many of them: FreeRTOS, RTEMS, QNX, VxWorks, and dozens more, of all sizes and varieties, and they are actively used.

Answer 2

QNX
:-)

Answer 3

In what sense is it promising?
You need to understand that each OS has its own niche in which it lives. If there is no niche, the OS dies.