PCs and NPCs might have different stats and abilities, but that's a matter of convenience for the sake of bookkeeping. The fundamental reality of the game-world must be that PCs and NPCs are identical, because the concept of PC or NPC is not something that exists within the game world.
The concept of Feats is also not something that exists within the game world. And the rules don't model the world (not even in 3e!), they only model some of the on-camera interaction between the PCs and the world. It would be a pretty weird and impoverished world that was restricted to the rules in the books.