Add to that, has even a 4 core Penryn come even remotely close the amount of math it can do in comparison to years old R580?
If Folding at Home is any indication of relative realworld workload and potential Physics performance then it'll still be years (Larrabee perhaps?) until Intel matches R580 much less anything newer.
Then again I'm not an expert in this area so I could be attributing far too much importance to GPU performance in FAH.
And the amount of physics used in Crysis is indeed magnitudes higher than those used in Farcry. It's not just a simple evolutionary rise in useage. The complexity of the calculations might have only gone up slightly but the sheer number of calculations going on in any given scene absolutely dwarfs those used in Farcry.
It can, of course, be argued that games don't need that level of physic nor that number of calculations per scene. But I would argue it goes a long ways towards immersion and the all important WOW factor. I'll be a sad buddha if the trend reverts to doing less because it isn't "needed."