How are the prices high?
Take the RT model for example. It comes with 32GB of internal storage, so let's compare it to the 32GB 3rd gen iPad.
For the same price you get twice the memory and better cameras, a quad core processor instead of the iPad's dual, a slightly bigger screen with lower resolution all in a lighter device. In my opinion the better specs vastly outweigh the lower resolution.
The non RT model has a bigger screen, twice the internal storage, and a better processor, so I'm not surprised that it costs $200 more, and the third model can work as two connected devices.