I think the word abstraction here is overloaded. OOP is also fundamentally driven by abstractions. The difference is that FP abstractions are mathematical abstractions, while OOP starts with human-centric conceptual abstractions - the kind every two year old is taught. These are not the same in terms of cognitive understanding. I also use FP approaches all the time in OO languages (like C#), which I believe is more aligned with where the general purpose language world is moving.