It's way too early to expect that. The market is not very liquid and with Amazon's volume, they risk not being able to easily settle to fiat currency without losses. I don't think a company of Amazon's size can just set up a Bitpay account, nor would they want to. Then there's the scalability aspect to consider.

I could see it years down the road if/when the markets are more liquid and Lightning is more ubiquitous and easy-to-use. Until then, you can buy Amazon gift cards with bitcoins. I buy them through the Bitpay wallet myself.