> I find this hard to believe. C++ does not have any construct that cannot be replicated, or is not common, in C.

But this is not a valid argument, as all languages are Turing complete, and most modern languages can do low level stuff at optimum speeds. As an extreme example, in Java, you could just allocate a large chunk of memory and run an allocator inside of it and sidestep the GC entirely.

With a programming language the question is thus not what can you do with it and how fast can it run with infinite effort, but what are the ergonomics, and what performance will you get in practice.