Please don't post in the flamewar style to HN. It's destructive of curious conversation, which is what we're going for here.
Microsoft writes much of the kernel in (msvc) C++ but they're keenly investigating other languages. They're also researching designs for new ones.
C isn't the only game in town.
In case you missed the message, C is deprecated on Windows, any updates beyond C89 are done as side effect of ISO C++ compliance, and UWP, including universal drivers, is not going away no matter how a couple few might hate it.
BSD is becoming irrelevant in world at large, so that would just be a waste of time.
In any case, the bazaar has proven that it is only technically able to produce UNIX clones.
/sarcasm ooooooooofffffff