The 55% profit margin is nonsense. That 55% is the difference between the cost to build an iPhone and the end user sales price. This is not how you calculate profit.
First, Apple keeps profits for (Apple the hardware/software manufacturer) and (Apple the retailer) separate. If you buy an iMac for $999 at an Apple Store, (Apple the hardware manufacturer) doesn't count it as $999, but as whatever an independent retailer would pay to Apple for an iMac, say $800. Same with the iPhone. So Apple will count the iPhone only as say $500 instead of $599, so that the Apple Retail Store can make a bit of money from the difference between $500 and $599.
Next, Apple's cost is not the cost of building an iPhone. You have to add cost of shipping, warranty replacements, support. If Apple builds 1,000,000 iPhones, some will be broken, lost, stolen, left in a box under some staircase, all that needs to be added. When you take everything into account, you get gross margin - gross margin is how much Apple is better off if _you_ go into a store and buy one iPhone instead of buying a Razr or Treo or whatever. Expect gross margin to be more like 30%.
Then you subtract development cost, cost of advertising, paying for all the managers sitting in management meetings, all the cost that Apple has whether _you_ buy a phone or not. When you subtract that, then you end up with profit margin, and that is likely around 10% - 15% and not more.