You are seeing it only from the technical point of view.
UNIX and C were developed together. Like most system programming languages before it, and even those that failed in the market, C's original purpose was to bring its host OS to life.
So to remove C from a UNIX compatible OS, you need to remove C from UNIX culture, which is impossible.
The resulting OS wouldn't be UNIX any longer, it would be Plan9, Inferno, something else.
As for C++, is pretty popular nowadays because it also came from AT&T, so it has been part of the UNIX culture from the mid-80's. But never at kernel level.
There are OS written in C++, like Symbian, BeOS, IBM i and others. None of them are UNIX compatible OSs.
I cannot imagine any commercial UNIX vendor to allow anything else other than C on their kernels, nor I do see it happen in the FOSS world.
Alternative OS that try to research new paths in OS architectures, yes. But not OS that try to clone UNIX culture.
If you look at my comment history, I am not very found of C, but I just don't see it happen from the social point of view of how comunities behave.
There's no requirement for Linux to follow UNIX culture. People are already arguing that Fedora, Arch, etc. aren't UNIX in terms of culture and philosophy, and the variances are increasingly Linux-specific.
(And I'm personally not a fan of UNIX culture, at least in 2015, partly _because_ it's a culture that thinks C is a defensible language to program in, at least in 2015.)
UNIX and C were developed together. Like most system programming languages before it, and even those that failed in the market, C's original purpose was to bring its host OS to life.
So to remove C from a UNIX compatible OS, you need to remove C from UNIX culture, which is impossible.
The resulting OS wouldn't be UNIX any longer, it would be Plan9, Inferno, something else.
As for C++, is pretty popular nowadays because it also came from AT&T, so it has been part of the UNIX culture from the mid-80's. But never at kernel level.
There are OS written in C++, like Symbian, BeOS, IBM i and others. None of them are UNIX compatible OSs.
I cannot imagine any commercial UNIX vendor to allow anything else other than C on their kernels, nor I do see it happen in the FOSS world.
Alternative OS that try to research new paths in OS architectures, yes. But not OS that try to clone UNIX culture.
If you look at my comment history, I am not very found of C, but I just don't see it happen from the social point of view of how comunities behave.