ok, this data deserves a nice discussion.
Apple reached the limit of what a premium 4" phone can do, and that's 4.5 billion profit per quarter (+-). If they want to earn marketshare to give more power to iOS, they need:
a) a cheaper iPhone line (like macbook air and pro);
b) a bigger screen iPhone to lure costumers away form samsung, htc and sony;
c) both a) and b), my favourite. So 3 iphone lines.
If they do not want to produce a newer cheaper...