While this is technically true it's not exactly the case. iOS users tend to be of higher income than Android users within a specific country especially in the west.

http://www.businessinsider.com/android-is-for-poor-people-ma...

When it comes to differences between countries its more about social perspective and Apple's operation within each country.

Apple has a huge share of the mobile market in China because having an Apple device is pretty much mandatory as a status symbol there, in South Korea on the other hand Android dominates at over 85% of the market share because of Samsung and LG.

In many European countries Android has the majority of the market share even in very wealthy ones like Germany and the nordic states because of various political and social views and that Apple hasn't been kind to many of the smaller European countries as far as support goes.

Overall in Europe Android's market share is well above 75% and you can't really call them a poor country, the UK probably has the biggest iOS market share in Europe and that's because Apple has a big operation in the UK and the Brits really want to feel American.

Sure if you bring in countries which are extreme cases like Nigeria you'll get a completely skewed picture but mobile phone manufacturers have special devices for emerging markets which are considerably cheaper in many cases running a very limited version of Android (and no Google Play) or some homebrew OS, there aren't that many iPhones in Nigeria but there aren't that many "Samsung Galaxy Edge S plus 6 Curve's" either...