> No, the system API of those systems is exposed in C, ObjC and C respectively.

This is incorrect. Microsoft doesn't have a C compiler, only a C++ compiler, so the lower level language on Windows is C++. Yet for application development, the application language is C#.

On Apple, the lowest level language is ObjC, and the application language is Swift. And on Android, its C + Kotlin.

Doing application development on, e.g., Android, using the C NDK, is pretty much unsupported, since the NDK is mostly undocumented, and changes often. The only stable API for application development is Java, or Kotlin.

It's still C all the way down, even in 2019. Amazing how far crappy, badly thought out, ubiquitous, low entry barrier languages can go. More than 40 years of memory errors, out of bounds errors, broken metaprogramming, undefined behavior, lack of error handling, type safety, abstractions and intelligent design in general, all served under the clunky syntax sauce. And it still powers our world. Worse is better, indeed.

> crappy, badly thought out, ubiquitous, low entry barrier languages

It is easy to criticize designs that are 47 years old in today's context.

I am betting you wouldn't have done a better job half a century ago either.