hmm... I guess I'm in the minority here. I bought my N64 for Mario 64 and Zelda, GameCube for Eternal Darkness, Wii for Zelda, Xbox for Halo, Xbox 360 because my Xbox died, and my PS3 for GoW. Heck, I even spent $1,200 bucks to upgrade my PC to play Half Life 2, back in the day. To be truthful though, I would never say that I bought the console solely for the exclusive(s) (except upgrading the PC and the Wii) but it usually is the thing that tips the scale.
While not very scientific, everyone that I know that has a console has bought it because they wanted to play game X and the exclusives were the ones that tipped them one way or the other. I want to play rock band but GoW pushed me to buy the PS3. I want to play CoD but Halo pushed me to buy the 360. Sure, they tell their spouse its for all the reasons stated in the study, but it really is so they can play X.
I think a better study would be to look at people that just bought a console and ask them what made the decision to go for either a 360 or PS3. That might give a better idea around the importance of exclusives.
Beside, is there any other reason to buy a Wii except for the exclusives???