Wow, you guys really don't get it. Apple (and apparently Google) threw the first punches. Amazon probably has sales data that tells them they are the #1 seller of Chromecast devices, and the #2 seller of Apple TV boxes. They've probably submitted apps and channels to Apple and Google multiple times over the last couple of years, and been rejected or delayed or ignored often enough that they've decided to respond. Apple TV is an also-ran at this point, and if they want to be the market leader, they have to support all of the biggest content providers.
You say we don't get it, but you just speculate, and speculate quite poorly.
tvOS was announced less than a month ago, and the developer kit has been out for mere weeks. How is possible, as you say, that Amazon probably submitted apps to Apple many times over the last couple of years? That's nonsense.
Moreover, how can you speculate that they've probably been rejected or delayed or ignored when the Amazon Prime Video apps are available on iPhone and iPad, work well, take advantage of AirPlay, and receive frequent updates?
As for Google, they seem to approve apps without any review. They barely block apps that contain malware. I don't believe for a second they would block a good useful app. Also, AndroidTV hasn't been out for years, as you suggest.
If we're going to speculate, let's at least make up some stuff that believable. Maybe Amazon is renegotiating their contracts with the content providers, and it turned out that their contracts would be cheaper if the contact was available on fewer devices. (
e.g., large price per show if available through amazons app on roku, firetv, apple tv, chromecast, etc; small price per show if available through amazons app only on firetv). At least that conjure is supported by logic and history.