Because in practice it’s really hard to not succumb to C++ feature creep. You start with good intentions and limit yourself to namespaces and structs, but then the “this will benefit from a vector, or this from a map” appears, then you realize you’d like a templated use case, and a single raw pointer or resource handle from a call to something like fopen() suddenly is not releasing its resource on a linked list pop and now you’re writing move semantics on top of copy semantics because a destructor declaration silently enforces copies on a std::move without move semantics. You reach for a unique pointer and, and all of a sudden, you have most of modern C++ without a single virtual call.

So people obsess over C because you’re hard limited by the upper feature bound. And that’s not so bad because C gets feature updates too - microscopic but effective feature updates; see C29 for the poor man’s RAII: defer

I generally like "C-style C++", but I find it difficult to draw the line between C and C++. It's too easy to keep reaching into C++ for "just one more thing."

That may be a me problem.

T> here is no runtime penalty for using C++

Large portions of the standard lib depend on heap allocations. C is a much safer target for environments with limited resources.

There is a huge mental overhead penalty...

It's what we did at amzn in 1994 ...