Are you sure about the supposition that retailers make 1/3 profit? I'm not so sure. Game consoles, for instance, are usually sold for only a few dollars of markup and the retailers depend on things like sales of games, controllers, and other accessories to make selling the actual console worthwhile.

I assume that an iPod is less this way, but still a 33% margin sounds a bit high for a consumer electronic device ... maybe it's different with Apple's philosophy, but in general I doubt there's that much profit to be found in MP3 players -- they may depend on the sales of headphones, cases, iTunes/Amazon gift cards or tracks, CDs to rip onto the device, etc. more than on the actual sale of the device.