I don't think Amazon "crippled" the DX. I'm sure they are aware of the limitations and that they did what they could within the limitations of time, price and reliability. My guess is that due to the screen size they struggled to get the price under $500 and due to a desire to get the device out in time to implement textbook usage for next fall they rushed the release.
It's actually pretty apparent that the real money in ebooks is selling ebooks, not selling devices. The model is give away the razor and sell the razor blades, give away the printer and sell the ink, model.
In order to achieve cheap costs, they need manufacturing experience and higher demand. I remember when a cheap pocket calculation cost several hundred dollars.