All games are rated based against their competition. So yes the competition is higher thus it takes more now. At the same time games now have the advantage of using elements that did or did not work in past games(for instance camera control in 3d games has been a work in progress for about 20 years now).
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut







