It's a given that iPhone sales will always be phenomenal--there's a built-in, essentially captive audience, because there is no significant variety of new hardware. If there was only one Android phone (like a Nexus or Moto X), I daresay that it would match, if not surpass, worldwide sales of the iPhone. But there is a huge variety of Android phones (many of them excellent and on par with the iPhone), so there's no way any one phone could outsell the iPhone.