NOT profit: ignores apples development costs
Your analysis just looks at marginal costs, and completely ignores the sunk R&D costs apple put into the iPhone.
Apple has put significant resources into developing the iPhone over the years, and needs to cover that. I imagine the iPhone won't actually break even until end of this year. While a lot of the dev costs are shared with desktop-OS X, much of them (e.g. UI/hardware) are new.