PS3 and XBOX 360 games already have some pretty spectacular graphics so i think people are used to that by now. If anything i believe what fools people is when they show cutscenes instead of actual gameplay.
Graphics are good on PS3/360, but if you look at some of the starter games on PS4/Xbox One you can see a very clear difference, they look like high end PC games right out of the gate and better than anything shown this gen. Considering the fact that it takes a few years for developers to fully get the hang of the hardware (look at 1st year PS3/Xbox 360 games to what is produced now, it's a drastic difference), you can imagine how ridiculous it will be a few years from now.
I agree, though, the leap from PS3 to PS4 will not be as close to what it was from PS2 to PS3 and people are so used to HD that it's mostly just about the games rather than graphics for next gen.
I'd lie if I said the graphics on FF15/Infamous/The Division etc didn't turn my inner nerd on, though.