R+D, marketing, human resources, etc. We don't know about that stuff and we can't even really speculate on it. All we know is how much the parts cost, and it is clear that Apple is making a killing on the device. Remember, most of this device dates back years. The screen is from 2007 and the processor is from 2011. The only major difference here is the shell.
More importantly, how do you calculate the benefit of getting someone into the Apple ecosystem so that they start with an iPod Touch (me) and end up with several iPods, Apple computers, an Apple TV, an iPhone, etc., etc.?
In the end, what we are seeing are two competing business models: one dependent on hardware and the other dependent on ecosystems (Google, Amazon, etc.). Apple doesn't (apparently) make much money off of the apps, books, and music. If the hardware one has worse specs than the ecosystem one, and it costs more, the business model is looking pretty bad to me.