This makes a lot of sense, particularly with the structure of having a two-tiered polycarbonate model + premium model (5s), and will address many psychological aspects of iPhone purchasing:
-Emphasize and point out the "pro" aspects of the iPhone 5s, increasing premium feel, exclusivity, and incentivizing the upsell from the polycarbonate iPhone (especially as there won't be a black version of the polycarbonate variety).
-People who want a new phone but "don't need" the iPhone 5s (in my experience there are a lot out there that think like this).
-People who can can only afford the cheapest phone, but won't feel insecure about this, as it will be outwardly indistinguishable from the higher end polycarb iPhone.
-It allows Apple to diversify the line up (thus allowing people to chose a version/color compatible with their sense of identity), while maintaining its characteristic simplicity/focus.
-Parents don't want to give their kids luxurious aluminum and glass phones for them to stomp on at a Justin Beiber concert.
It also makes sense economically:
-Improved margins compared to selling the 5 and 4s (polycarb will be easier to manufacture and will benefit from larger scale pricing of homogeneous components).
-This year's mid tier poly carb iPhones will be next year's refurbs, thus covering the budget of the vast majority of worldwide smartphone buyers.
Edited by PatchyThePirate - 7/24/13 at 4:11pm