Is the reason Amazon isn't releasing this for iOS because of Apple's closed ecosystem or is Google just a bigger competitive threat?
> 2.25 Apps that display Apps other than your own for purchase or promotion in a manner similar to or confusing with the App Store will be rejected
[0] https://developer.apple.com/app-store/review/guidelines/
1. Allow installs from unknown sources 2. Download and install apk.
Can't do that on iOS without jailbreaking.
I don't think Amazon would want to launch a product dependent on JailBreaking. Unless Apple is forced to provide an API for alternative app stores, I can't see this ever being allowed. Unless of course apple rips off the idea and does it themselves.
On the other hand, apple could just throw more money into securing the phones from jailbreaking and end the business model much easier.