Embedded Systems are quite varied these days. The one in the article sounds more at the high end of the scale. In more resource constrained environments, C is still the king. ( though I'd prefer something far more robust than C that works well on resource constrained platforms and cross compiles to ansi C ).
I think once your system is large enough, C++ is not your only option, many languages can be used.
I think once your system is large enough, C++ is not your only option, many languages can be used.