Josiah said:well, real-time graphics IS reaching a point of diminishing returns....if you have one console that can do 1 billion PPS, and another that can do 2 billion PPS, the 2x difference in speed translates to very little visual difference (I know it's a stupid example, but you get my point)
Maybe for the models in games, but you could always just do twice as many monsters on screen or enviroments twice the size.(well, assuming the rest of the system can handle it...and I guess that'd matter more for having many characters on screen at once than a large enviroment, as once you get far into the distance you can't really see anything...but enviroments could be more complex, make everything an approximate perfect circle!)