Strongly disagree here. Graphics are part of it, but not the whole story. These machines are both currently slow in many ways, the GPU and CPU are architecture from '04 I believe, that is ancient in tech years. Graphics will greatly improve just as they always do, no question about it. Look at a PS2>PS3 game or XBOX>360 game for comparison and those were 4-6 years between releases. A lot changes.
True actual 1080p and 60FPS standard across all games next go around. Current games reach maximum 720 lines of resolution because the graphics cards are pretty butt. The stuff that is wowing everyone is mostly smoke and mirrors. Bloom effects, motion blur, that cartoonish look that games have now are all ways for devs to make it look better.
If the 360 utilizes blu ray as the P4 will then you can this time around have more larger scale games and bigger worlds. Not that BS Sony was spouting because the P3 even with Blu ray was too crippled in the RAM dept. to do much with it, as well as the read speed of their drive was too slow.
Speaking of RAM that is a major gimp currently as well. There is no magical process where these systems have untapped potential. That is developer speak they always use for sales. Everyone in the gaming community knows that. Uncharted 2 was about as good as the P3 could do, and Gears 2 was about the best the 360 could do. Both were in 2009.
It will be the same as every other time. Once the new ones finally do come out people will be in awe of what the developers accomplish with them. Some more casual types are fine with bad hardware for another 5 years, you all can have it since they will make games for the 360 and P3 after the new ones, a lot of us and it is a lot are wanting new stuff and have been for awhile.