I hear this claim quite often, but I have yet to see it documented. I'm not saying you are wrong, just asking if you have some link to a study supporting this argument or anything similar.
The android sales numbers for apps are public (the range of sales anyway). I have a top selling iPhone app and it's fairly easy to compare with the top selling android apps of the same rank and see that the sales are an order of magnitude off. Also I've talked to many developers for android and iOS and they say the same. iOS sales are often an order of magnitude higher.