The difference, I think, is that much of that is not the easy path. Being able to make parent-child-parent-child calls is the thing that distinguishes inheritance from other kinds of polymorphism, and it leads to really bad code. No other kind of polymorphism has this upcall-downcall-upcall-downcall pattern baked into its structure.

The case I'm talking about is a perfect fit for inheritance. If not there, then where?