Let me just clarify why power is irrelevant to FPS.
InFamous 2 could've ran at 60 fps. There's nothing saying it can't. Maybe GTA V ported to a PS4 would've run at 60 fps. But then what? You have a game that looks exactly like last gen, but runs at twice the fps.
Next gen won't change. You'll want to use all the power you have to make a picture that's at pretty as possible. In an open world, especially, you cannot control what assets are loaded and what's in view to the same extent, and as such would sacrifice too much to get 60 fps.
So, sure, you can get a 60 fps game, but it would, semantically, look "half as impressive". It's a choice to spend the power to have a complex and alive world, in exchange for 60 fps. Unless next gen is quantum computers that give developers more power than a dev can use, then you'd get 60 fps.