Not only that Android is cheaper but also the mean income in countries where Android is prevalent is lower than those where iOS is, with exceptions like Germany, France (I'd need to see market share data from these exceptions)
iOS popularity correlates more with the use of English as a first language than mean income: Germany and France are huge "exceptions" for income.
In all likelihood, iPhone popularity is cultural (i.e. popular in the Anglosphere), which has an incestuous media/advertising landscape where Apple is seen as cool/hip.
