Not really, otherwise even the standard library would not exist, and we would manually ask pages to the kernel every time we want memory.

C, as a language, is indeed low level, but that does not mean that programs and libraries shouldn't build abstractions on top of the low level interface.

Not at all. The point of C is to have as much abstraction as possible while still allowing maximal control. And 'as much abstraction as possible' is a matter of historical context, since we learn all the time that there are better ways of doing abstraction than C does.