EDIT: make that more than 1 billion iOS devices: http://www.macrumors.com/2015/01/27/apple-one-billion-ios-de...
I'm thinking more along the lines of: Human, at one point or another, before ever purchasing their first iWhatever, learns or hears about the Steve Jobs' story, which symbolizes something bigger than themselves. An idea they want to, in some small way, be a part of.
Also, I wouldn't say the story necessarily captivates people in the US as much because we are "living the dream" so to speak being here. But for most of the world it is only an idea that is at least an ocean away.
I don't think it's correct to say that just because alot of a certain product has been purchased that means it can't be a status symbol. Regardless, 500M is still only about 15% of the world population, and I think it would be an oversight to think that 500M number represents completely unique individuals.
1) Steve Jobs' story 2) "Apple as a status symbol"
#1 will probably make them strong for a long time in the consumer's eye, but #2 will fade with time, as I think it's safe to say open-source is a provably stronger model than closed-source. As long as they embrace closed-source, innovation on their platforms will suffer in the long run, and as a result they will (over time) be incapable of producing a better product than their competition.