I don't think it's fair to underestimate the research and development costs to create a new product; remember that the PS3, when including R&D, cost over $900 per unit during its first year on sale. It can take a long time for those not insignificant costs to be spread out enough that the product will actually break even, same with marketing (which will also be an ongoing cost), distribution, staff-training, support etc.
To be frank; there's no point in totalling up the parts in the device, as you're not buying a collection of parts, you're buying the product that they make, and that's a very different thing.
It's the same when people discuss self-building computers; yes, individual parts might cost you less if you build them yourselves, but if a manufacturer can take those same parts and put them in a smaller, specialised package, then you're not just paying for the parts anymore, and nor should you expect to be.