I think a high percentage of amazon customers opt for the free shipping option which can take 2+ weeks. Waiting for bitcoin to confirm, on top of a 2 week shipping time may not be that much of an inconvenience.
The "scaling problem" could be a good problem to have. One way of viewing it is: "bitcoin can't be used to buy a cup of coffee and isn't ready for a prime time, mainstream, role". The flipside of that might say that if bitcoin's network lacks the transactional volume to cover all transactions, retailers might expand their platform to include support for other crypto to fill the vacuum. One perspective is likely over-optimistic while the other is the opposite. The likely outcome could be somewhere inbetween the two.
Bitpay green lights transactions on the 1st confirmation which isn't too bad.
Amazon accepting bitcoin would be similar to an official endorsement. If the public sees amazon endorsing bitcoin while banker CEO's condemn bitcoin it will create a divide, a conflict of mainstream opinion as opposed to the typical unified front the media is often able to maintain. That could encourage the public to research and learn about crypto more rather than believe the mainstream media angle of it being a bubble, which could be a good thing even if transactions aren't instantaneous.
Thinking this way it makes sense. We are not talking about perishable food items that must be bought and consumed fast, we are talking about other products that don't have expiration date, so there isn't any problem in waiting some days or even weeks as you said to have the product sent. It's enough time to have the transaction finished paying a lower fee and if the transaction cancels because a very low fee reason, just cancel the package as well, it works fine.
And a big business like this can really make more people start thinking about Bitcoin and its advantages. There are many people who use Amazon services, but don't know or don't have interest in BTCs yet, but after an adoption like that it's possible that these people change their minds and spread the word about Crypto-Currency. It's good especially to make more sellers adopt BTC.
Still merchants won't process your order/s until after a decent number of confirmations on your transaction has been received so if you put a low fee and it took a few days before it reached the minimum confirmations, your order could be delayed and might no longer fit to the stated free shipping time frame.
So In conclusion to that I think its still a problem although I'm sure there are users who are still willing to pay high fees for fast confirmation.