New e-book reader from Sony

Kindle competition is heating up.

I can't for the life of me understand why Amazon would want to compete with Sony. Why aren't they opening the Kindle store to devices like the Sony e-reader? That would be the best possible scenario: let the hardware companies do what they do, and let Amazon dominate the market for content.

At its heart, the Kindle store represents a viable shot at being the marketplace for books in the digital world. That would be a major coup for Amazon- and seemingly is the strategic goal behind the Kindle effort- but I don't think they can get there if they don't open the store up to other hardware devices.

Perhaps Amazon's trying to do this but Sony wants to retain control of their own store.

That's the only possible explanation I can come up with, and it would be very short-sighted on Sony's part if true.