Looking at the embedded market OSes, everyone is pretty keen in moving away from Linux into RTOS, mbed, NuttX, Tizen IoT, RIOT, eventually Fuchsia, ....
Who knows which ones will survive, however they all have two things in common, they aren't GPL based and just enough POSIX to keep C and C++ happy. Additionally some of them do have stable ABI for drivers.
Linux's long term victory might be constrained to the server room, and even there it is debatable, given the increase in managed runtimes for micro-services, which could even be running bare metal for what I care.
Who knows which ones will survive, however they all have two things in common, they aren't GPL based and just enough POSIX to keep C and C++ happy. Additionally some of them do have stable ABI for drivers.
Linux's long term victory might be constrained to the server room, and even there it is debatable, given the increase in managed runtimes for micro-services, which could even be running bare metal for what I care.