Well, I have a few rhetorical question for you:
1 - is Infamous running in 1080p at 60fps or more all the time?... Could it benefit from running in 4K? at a better frame rate?
2 - Infamous 2 is the best looking console game so far, and there are still visible concessions (not all lights cast shadows, no water puddles interaction).
This is for the PS4, if you ask these question about the xb1 and wii-u it's even more obvious that there is ample room for improvement!
I think the PS4 in particular is a pretty nice piece of hardware, and it's more and more obvious with every game I play on it, you cannot find a better gaming machine for 400$, however if Sony made a 500 or 600$ machine it would be significantly improved and games would benefit from it (Assuming they take the same loss/gain on every machine they sell).
