Apple brought touchscreen phones to the mainstream. They are in the unique position of having their "cult" that will stay loyal regardless.
They also have unlimited goodwill from the media types who tend to do their work on Apple's machines. This is part of the underrated aspect of their success, whereby the media types will back Apple regardless of whether they have the best device on the market.
Not forgetting the apparently simplistic user interface. Like it or not, most people in the World, and the USA, are not the smartest. Just as the top 5% may own the majority of the wealth, the top 5% in intelligence is also a small number of people. Simple is good for the rich but stupid. There is also the high-priced status symbol aspect. Everyone knows Apple products do not come cheap. How else do phones such as the Arte, Vertu, Tag etc keep selling? And I know a couple of people with money who bought Arte and Vertu phones just because they are expensive and like the expensive materials used.
How will they(Apple) keep their high profits sustainable ?