I'd agree that throway's case was overstated. That said, Apple has built up its brand as being one of "quality" and "high end." It's a similar brand perception as Cadillac. If you have one, people assume you have the money to afford nicer things. That happens whether you bought because of that or not, and Apple knows this. If they start competing on price, they will sooner lose their luxury status.
I don’t think if you see someone with an iPhone, you assume they have the money to buy nice things. I think the image Apple has built up works in the opposite way. If you see someone without an iPhone, you assume they only bought that product because they couldn’t afford an iPhone. That must be the only reasonable explanation, you think, because who would willing buy another brand (due to the perceived difference in quality).