I never heard that Amazon did accept bitcoin already because I never use Amazon to buy any product, or maybe I am missing something before.
Maybe they will not use bitcoin in the near of this year or the next year, but we don't know what will they do if many online stores are using bitcoin as the alternative payment method.
The Amazon will make it easy to add bitcoin for a new option to their user because I am sure they still think about what will the benefit to them if they use bitcoin as the payment option.