Apple's competitive advantage has always been hardware-software integration, and user experience. In all of apple's products, I've always notice they try to widen the moat with their hardware and design capabilities (ie: reengineering of the MBP batteries, unibody chassis, multi-touch screens on phone/tablet, a4 chip, etc).

And if you look at Apple's iPhone Design page, it is devoted to mainly hardware upgrades and the marketing focuses on user-experience benefits of such upgrades. And these improvements just so happen to be in areas that aren't easily replicable by competitors like Google (because their expertise is in software).