One thing people keep forgetting, which amazes me considering the number of Slashdotters that have complained about the amount of non-technical user support they've had to do since the day the site first came online, is that the VAST majority of people really don't give a single shit about performance and speed as long as they can get Required Task Of The Moment done without it pissing them off.
My mom just replaced her 17" 2006 iMac. Did she think it was too slow? Not necessarily, she just knows from my experiences that a computer that old is likely to crap out and die -eventually-, and she might as well get a new one when she can do it, before that happens. She sure loves the speed of her new 27" iMac (which I suggested, mainly for the screen and her eyesight) but she really doesn't need it for more than managing photos, email, web browsing, and other "Mom" stuff.
Average users do not care about speed, they don't know a G5 from an i7, and many actively don't even want to be told. They want a device of some kind, traditionally called a "computer", that does a few things and does them with the least intrusion. Business uses, academic uses, and geek or gamer uses are completely different (and largely Windows PC based) - and they're a far, far smaller market than "Moms" are, even combined. If they're told that there's a new iDevice that lets them do email, photos, Facebook, web browsing and watch videos from the kids for only $1000 and it comes with a 20 hour battery they'll be whipping out the plastic.