Think about it. Apple is basically subsidizing all kinds of costs associated with keeping the same design as the iPhone 4. All that machinery and tooling used to produce casings and glass etc. etc. is expensive for Apple as well as their partners (Foxconn etc.) to purchase and assemble on lines. In order to keep the high margins Apple is known for they've got to minimize changes and keep to a 2 year cycle much like they do with their Mac line of computers. Intel does the same thing with their processors and it's referred in the industry as a "tick/tock" cadence. Tick being the 4, tock being an incremental improvement the 4s. We all hate it, but until Apple sees real competition in the smartphone arena in terms of % profit they'll continue to rest on their hardware laurels on the 2 year cycle.