Amazon has shown that they're open to pivots and trying new things before. I wouldn't be surprised if they made two different lines of Kindles, with different OS's. They are trying to achieve market dominance with the Amazon App Store—with WebOS they could truly achieve market dominance since they'd be the main source of apps.
But the Kindle Fire is supposed to be an appliance. It's supposed to Just Work. Adding a second tablet with a different OS would confuse Amazon's target audience.
there are two different kindle products - the e-ink kindle and the kindle fire. the e-ink kindle has a few different revisions with different input and connectivity methods, but in the end it is all the same functionality: the ability to read books, shop in the kindle store, and nothing else.
