I think early Next-Gen games shouldn't be more expensive than late current gen games....but think about it. Once developers have the final dev kits and figure out how to get most out of the hardware, there comes another graphical push plus stuff like more physics, better animations and more animation variety, and of course top-notch facial/performance capturing. That stuff costs a lot, and once customers are used to a certain standard, they won't accept anything less. Which means overall less AAA games as a whole, with even less risk taking when it comes to new IP. More publishers/developers will go out of business who won't keep up.
When I look at that new Unreal Engine 4 demo I wonder whether future games will continue with that trend of having linear film set like levels, or are they going to create large playgrounds with less fidelity?