If you open this Guide: http://tinyurl.com/FalconGuide about building yourself a PC and compare it with the Technical Specs of the current Consoles we are slowly getting to GameCube/Playstation compared to PC levels of differences again before the more "Advanced" consoles came out.
The Xbox360 for instance is placed somewhere a lot below the "Minimum" Spec with only 512MB RAM and the ATI Xenos (which is a hybrid between R580 and R600 from 2005-2006, those cards aren't even sold anymore for at least 3+ years). It is even below the "Destitute" build in things like Harddrive space, but especially most damning the amount of RAM.
Games on new consoles are going to get new things like Tesselation, Real Time Radiosity Lighting Technology, Bokeh, improved AI routine APIs etc. not to speak from increased resolutions and framerates (the current consoles love running games at or below 720p at ~30FPS) and level of detail/polygons on both models and textures that will make an immediate difference right out of the box.
Ultimately we are heading towards Real Time Raytracing, it might take another 10 or so years now till games will look like Pixar movies and games can be rendered real time to look like this:
For now they are still rendering those type of things on 32Core Supercomputers and it still isn't Real-Time
A new generation has been overdue for a few years at least already...