Don't ever think for a second that this isn't propoganda, because it is.
What I'm trying to say is that the average quality of the games on the PS3, or even square-enix's games probably won't look as good as the FF7 tech demo.
There has been a history of those companies giving us total bogus information on stats and power. Let's not forget PS2's 'emotion engine'.
Making a high quality (and very short) FF7 tech demo and a few screenshots is a hell of a lot different than releasing a game.
I don't even know whether to trust ANY of the stats for the new generation systems, since they're all subject to change (including the look of the console) in the future. This is merely propoganda from SE, Sony, Nintendo, and even Microsoft, to get you excited (and it's working).