I've been a C developer (among other things) for about 20 years or so, but I've always described my C++ skills as being "in the C with objects" range, I might have to change that to being "nearly in the C with objects" range.
And it's pretty simple to avoid all these warts, just... you know don't write them. On the other hand I don't have any experience with old C++ codebases, which is where you're likely to find this hellish stuff.
Ergo, no one is actually a real expert in a specific language.
Stroustrup is an expert at nailing legs to a dog and calling it an octopus.
No, they are experts on the implementations they created, not on the other ones that were created.