People are expecting to much from GT5, it will raise hardware in japan thats for sure, but in America it will have little impact on hardware, and in Europe it will raise hardware a little but not much, the holiday shopping spree and an hypothetical price cut would spur sales allot more the the launch of a single game
People should realize by now that, a single game this far in to the generation has little effect on hardware sales, price cuts and catalog of games are much more important than a single game