To the person who asked what resolution real life is .. Yes real life is not only stereoscopic, but also 20,000x20,000 pixels, or whatever the current best estimates are. But we can still be totally engaged by the postage stamp TV screen in front of us, showing the most artless home movie, with its 480 lines of res. So clearly, low res by itself isn't any barrier to realism. If we're not providing maximum impact over 480p already then increasing res doesn't bring anything much to the table.
As for gears or war. I haven't played it. I've stood behind some people playing it at a demo kiosk. And sorry, it doesn't come close to TV realism! it may be the most gritty and detailed 720p signal yet, but there is more realism and detail and persuasiveness in someones super-8 video of a child playing cowboys and indians, converted to VHS, and played on a 70s TV, than there is in this wide-bandwidth 720p signal of gears. So I'd say that all that silicon to make gears run at 720p would have been better spent on more geometry and more physics etc (motion blur, or 60fps), over a 480p signal.