Some friends of mine in Vietnam run a shop, in Hoi An. They make a comfortable for local standards income, but after tax rates and costs they will have about $10k a year, not to be sniffed at, but still, not amazing income. A younger sister wanted an iPhone, it was a running joke that if she bought one, she would be sleeping out in the pig sty, the 'adults' (those over 20) consider such things excessive waste of money, but she being 17 decided to spend her 3 months wage on a second hand iPhone 4. This isn't un-common, her peer group all feel the need of it. She could have had something like a Nokia 620 which has all the apps she uses anyway, for a fraction of the price and it would have the benefit of new battery life performance.
Hell I've seen shoes with the Apple logo put on them[0] there is most definitely a lot of brand power and loyalty in Vietnam and China. If they can ensure that people end up with the 'correct' Apple and not a nock off, they could do quite well. The fact that kids know how to tell the real iPhone from the fact clones is enough, as they create peer pressure for the real thing.
So yes, I can see Apple benefiting from a bunch of people in the emerging markets feeling they've 'made it' when they can afford an iPad, they still are a long way of affording a car.
That isn't a great metric without examining the pace of sales in the developed world, so you know what you're comparing. And has no connection to phone sales.
