Had a discussion with a level designer from 2K Games yesterday about this, he says you can do these sorts of graphics on any modern engine you just need the Artist's skill level to be high enough to do it. Mind you these were enclosed scenarios none of the games released on these engines would look anything like that just because its not game worthy, plus on top of that they get beasts of machines to actually demo this. All in all, you'll never actually see that quality in the tech demo in actual games, they're optimised to look pretty and not run well with 512+ particles systems all going at once as well as AI/Bots running around all the collision, system triggers and systems all doing there thing.
At least all I can say is technology is slowly getting better bit by bit but games will honestly not look any different for another 5-7 years, just look at the past its a perfect example, to me this demo looks barely any different from Unreal 3 when it first came out, they've just done a cinematic cut-scene with extremely detailed models.
