It doesn't hurt that the total number of constructs in K&R C is really quite small. I'm not sure there are any current languages with comparably few constructs; maybe Arc. Even Scheme is bigger, at least for a recent version (say, R6RS).
True, but the revolt against R6RS has been ... fierce. None of the new steering committee members was in favor of it and we expect a move back towards the old virtues.
Still, Scheme does try to address a lot of higher level things, e.g. the full numeric tower, whereas C shines as a universal very close to the metal assembler.