Looking at some old GPU articles...I think people really need to tone down their expectations.
The PS3's RSX is supposed to be slower than the 7900GT released that year. How much power did the 7900GT take under load? 50 watts.
Now, let's take a look at a high-end GPU from today: the GTX 580. How much power does it take under load? 300W.
The PS3 was a power hungry beast and it has a 225W PSU, which means its total draw is below that. Next generation consoles are likely going to take less power than that. Even mid-range GPUs like the 6850 or GTX 460 take 100-150W of power, so I wouldn't even expect that kind of GPU performance in a modern console anytime soon.