Why are people so insistent on saying that all the PS3 and XBox360 need is more RAM? Their GPU's are in the stoneage for today's standards - even if they had more RAM they would not run contemporary games on "Ultra" settings like a high-end PC would, which is the very *aim* of a console developer - offer good quality for a smaller price.
The WiiU has more RAM - check. Better GPU (likely) - check. What more could we want?
Basically because they are DX9 parts and while ancient DX10 and DX11 really didn't add much graphically. I believe 11 added some of the volumetric stuff.
Nothing to keep the 360 or the PS3 from doing native 1080P it they had enough RAM, I doubt your average person is going to look at a Wii-U game and a PS3 or 360 game and say "OMG The Wii-U blows the other two away!" Wii-U games are going to look better then PS3 or 360 games but not by a huge margin so thats why some people believe just adding some RAM to the PS3 and the 360 could work. Pull a Wii on Nintendo this time around so to speak.
We have hit a wall in terms of graphics for the time being, the Wii-U hits that wall quite nicely, I will be in line outside my local Toys R Us on launch day for the Wii-U.
A color framebuffer expanded from 720p to 1080p (assuming 24-bit color) only requires an extra few megabytes. Add a few more for the depth buffer. RAM is not the issue with getting PS3/360 games to run at 1080p. It's the GPU. If it's having a hard time rendering a scene at 720p, it'll have an even harder time with 1080p because the GPU has to processed a whole lot more pixels. How many more? About 2.25x more, and don't forget that each pixel goes through multiple rendering stages.
The big problem with your whole argument is that some games DO run at 1080P on the PS3 and the 360 and PC's with close to the same hardware (albeit with more VRAM.) also can play games at 1080P the main issue is textures, at high res they eat up the RAM like nothing else. Want photo realism in games? Easy enough just use photo's as textures for everything but you will also need a few hundred GB's of RAM.
It's not the GPU that is having the issues, the programmers have been having issues trying to cram enough textures into a 256MB space (less then 256 actually but thats a separate issue.)
http://www.escapistm...HD-Texture-Pack
The link above is a great example, the reason one looks better than the other is due to the high res textures. The reason you have to install them to the hard drive is that the disk drive isn't fast enough to stream them into RAM. If you had more RAM that wouldn't be an issue and the system wouldn't need to even stream from the hard drive saving even more resources so instead of waiting for textures from a slow drive they would already be there ready to draw.
Limited amounts of RAM like I said.