Accessories. By building the new iPhone 4S with nearly identical form factor as the previous 1.5 years if iPhone 4 to have not only a huge selection of accessories already on the shelves, but also build strong support from accessory makers who can keep selling its products longer, avoid new tooling costs. One could also say is another slap at the fragmentation of the Android market, where each phone needs a different case, so fewer vendors are willing to support them. I see a hell-of-a-lot more (cool) iPhone cases then compared to all the Android cases combined at BestBuy. Would not be surprised if the teen crowd demands iPhone simply based on the case.