This is not true:
Apple is now requiring third-party eBook sellers like Amazon to also make their titles available through the Apple store
Apple is NOT requiring Amazon's books to be listed in the Apple iBook Store. It's requiring the Kindle app to allow users to buy books within the Kindle app. Right now the Kindle app gives you a link to the Amazon website, where you can buy books.
It sounds like users can still go to the Amazon website to buy books, and not have to pay the 30% fee. Amazon just needs to give users the OPTION of buying books in-app and paying a 30% fee.