I saw Stroustrup give a talk and he said exactly this - C++ is a toolbox of different paradigms that aren't meant to be combined. If you avoid frameworks that impose a particular paradigm and/or shield the parts of the codebase with different paradigms (for example when using Qt you really should have your "engine" running aside the Qt rather than embedding the code in the UI, extreme example I know but the same idea) you'll have a grab bag of different approaches for the specific problem you're having for zero cost. When people talk of "sticking to a subset" they are unknowingly doing exactly that (especially since everyones subset is slightly different).

There might be a "culture of complexity" in the community, but to remove the conflicting paradigms from C++ is to destroy what makes C++ useful. I don't believe C++ is complex in it's DNA, but highly experimental, overwhelming to newcomers and experienced developers alike (since you have to truly understand any feature before using it), and easily misunderstood. It requires more strictness in design and implementation than other languages, and isn't my first choice for anything that doesn't require high performance. But since I'm in game development and audio synthesis, it's often my only choice since nothing else hits that sweet spot of abstraction and performance.