To what extent do you believe human beings are rational decision makersWatch
Similarly, people don't always opt for the cheapest good in the market, even if the law of demand states that it's high when prices reduce, abnormal often indicate otherwise. Also focus on how consumption has strongly linked to social status, and that welfare is usually higher when people consume goods of higher price and quality (for example, Veblen goods provide high consumer welfare simply due to the feeling of accomplishment or satisfaction one derives from being able to purchase such a good).
Try and analyze how marketing strategies also often try to distract people from rationality, and how they try to make people purchase their good regardless of price changes. Human irrationality combined with advertising strategy is probably why people purchase iPhones despite their high prices - though this can be looked at in combination with brand loyalty and Apple's market dominance.