Casual gamers have an excellent alternative in the nvidia shield TV, far superior as a steamer and a gaming solution to the ATV. If you wanted casual gaming , it's the clear winner.
Amazon will not release an Amazon app for iOS, they have too much invested in Prime, new top gear spin off etc, and will want to sell their own boxes. Slowly they are creating thier own ecosystem, an app for iOS would undo that, instead they offer a damn cheap firestick if you want to get into the ecosystem , something apple cannot do...thier entry box is $$$.
Be interesting what the top gear spin off does for sales numbers....I can see quite a few apple fans who like topgear getting a Amazon device to watch the show .