Amazon will adopt bitcoin in the future, there's no doubt about it, but it may be later than expected.
Optimistic, in my opinion. As someone already said, Amazon is a huge operation, and right now bitcoins wouldn't have a major dent in that. The gift card option is their best option it seems. No hassle, and they don't have to deal with it and still get guap.
Don't get me wrong, if Amazon does business with bitcoins directly, I think that would really get athe crypto-currency revolution rolling even faster