This conversation is no longer of any benefit, but for the sake of you and your co-workers... Saying that C is predictably inferior, more expensive, and less maintainable shows a blatant amount of incompetence on how either languages operate. C++ only offers abstractions to (debatably) more easily allow for an object oriented design for codebases. Semantically everything that you can do in C++, you can do in C.

There are plenty of features in C++ that are beneficial, particularly the handful of mechanisms that allow you to move away from #defines, but to compare performance between C and C++ simply shows ignorance.