Here's a fun thing to consider, since the PlayStation two I don't believe the graphics have gotten much better in video games at all. This is gonna take a little bit of explaining.
Sure the poly counts of gotten better the textures have gotten better anti aliasing shadows all that crap has gotten better... However look at a game like Psychonauts, would higher polygon counts make the game better? Would more lighting effects make the game just fantastic?
Take a look at the game Crysis, when everything is moving tell me that it's just not as easy to see your enemies as it would be in a game where all the scenery didn't move. See your enemies are crack shots, they can see you no matter what, all the scenery moving only affects your ability to see them... Crysis is a very pretty looking game, but it sacrifices some of the playability to look that good.
Back to Psychonauts, all the game could really use is just higher resolution textures, that's it.
But then take a look at a game like skyrim, Bethesda did such a crappy job texturing the game that even using their high resolution texture pack the game doesn't look that good. However other people have taken that game and re-textured everything, was lower resolution textures, but they look like they are higher resolution.
The further we push technology the crapier and lazier the devs are actually going to be when it comes to graphics, they get four gigs of RAM there to use that four gigs of RAM regardless if the game could actually use it or not. they're not going to try and make the littlest texture possible that looks the best, they will use the bigger texture even if it looks like crap just because its bigger.