I agree with the earlier Apple/iPod comment.
Amazon has seen what Apple has done with the iPod and iTunes store. (#1 selling player and #1 Music store... all accomplished in a closed system). I would be willing to bet that Amazon will continue to employ the same model.
You can cry "Open" "Open" "Open" all you want, but in the face of reality, "Closed" has been the most successful digital distribution model so far.
I am not saying it cant change, but.......