"People are generally incapable of abstraction. If you are the "x of y"" -> That's not abstraction, that's metaphor, and people are very capable it. In fact, it's how we do most of our thinking.
Is a metaphor not a type of abstraction? At any rate, you're correct, I'm probably not giving people enough credit. I'd say that if you can avoid "X of Y"-isms, you're better off doing so.