One thing that I'm surprised this doesn't cover, especially since it's so C++-centric, is that modern C++ OOP is much more defined by lifetime/scope management

One thing that I'm surprised this doesn't cover, especially since it's so C++-centric, is that modern C++ OOP is much more defined by lifetime/scope management than anything else. What defines something as an object is the fact that it doesn't exist until it is constructed, and doesn't exist after it gets destructed (which is the case even for fundamental types, with the exception of char/std::byte, btw). Hot take: RAII has basically taken over everything else as far as structural design foundation goes. Type erasure and encapsulation still play a role, but it's not nearly as fundamental anymore.