In a low-level embedded environment some of the "software engineers" will have an EE background and have barely mastered C. C++ is more complex and some of these guys are simply afraid to learn a new language. Thus C is used as the lowest common denominator. (Before you suggest getting rid of these guys, they're at least as important as the CS majors who don't understand the hardcore analog stuff.)
Speaking from experience in having inherited and maintained both: a horrible design in C is difficult to understand, unwind, and refactor into something usable.
A horrible design in C++ is infinitely worse as random layers of abstraction send your brain careening around the codebase trying to figure out which code is going to be executed in which circumstance.
If I have to work with engineers who I know will not produce great designs, I'd much rather have the former than the latter.
