> Using a feature in C++ means carrying along all of the baggage from its dependencies and interactions with every other feature.
Only if you use every other feature. Don't do that. Use the features you need (and understand well), not every feature. It actually becomes much like you say C is, except that you don't have to write the features.
Not true at all. A lot of the features have either an interface or an implementation driven by the possibility of combination with some other feature. The cognitive and/or performance costs remain even if that other feature isn't used. For example, it's easy to get mired in writing extra constructors/destructors and virtual hooha just because someone using your class might also use some feature besides the one you used yourself. I've seen that happen on many projects. The only way to avoid it seems to be to abandon most of what makes C++ different than C, at which point it would usually make more sense to start with C and add what you need.
> For example, it's easy to get mired in writing extra constructors/destructors and virtual hooha just because someone using your class might also use some feature besides the one you used yourself.
I don't think I've ever seen that. (In a library, sure. In application code, no.) If you know it's going to be needed (or you know it's very likely), sure. If not, every place I've worked in added the extra constructors when needed, and only when needed.
Extra destructors? Other than empty destructors, I don't think it's possible to create an "extra" destructor, because each class can only have one. (And, in the case of virtual destructors, adding them is good practice. But that's not "combination of features", it's part of the deal you sign up for when you start using polymorphism. (Though I guess you could describe it as the combination of destructors and polymorphism, which is true, but it's simple enough I have a hard time regarding it as out-of-control complexity explosion.))
It has been a long time since I worked on an application so trivial that parts of it weren't broken out into separate libraries. Most often, those libraries end up being maintained by people other than their users, and the users always end up using the library in unexpected ways or contexts so these protective measures always become necessary.
Perhaps more to the point, I don't think there should even be multiple constructors each called in different situations that it takes several pages to describe. This complexity mostly exists because the people who defined C++ don't seem to understand the significance of value vs. reference semantics, as the OP also noted. Move semantics and rvalue references represent a tacit omission that the previous semantics were broken, but they just introduce even more non-intuitive syntax and another few pages to describe what happens in which situations. That's exactly the kind of spurious complexity that makes compiler writers want to go on killing sprees and folks like me want to avoid the whole morass.
Only if you use every other feature. Don't do that. Use the features you need (and understand well), not every feature. It actually becomes much like you say C is, except that you don't have to write the features.