I can hardly wait to subscribe to Mac OS on whatever hardware/platform I'd like too! /sarcasm
This is part of my main gripe with Apple. Simply put from Apple, "A 'walled garden' of both hardware and software is the only way to protect and provide the best experience for users". Except it wasn't and isn't. iTunes was allowed on Windows to sync iPODs, pretty much from day one, because money. They knew there was no way potential customers were going to switch to MACs to simply own an iPOD; they had to tap the Windows market or continue to struggle. Being able to steal digital music was also a key component. And because of that, we now have the success of Apple mobile hardware and streaming services, all because of a more open, cross compatibility approach to get iPods into the market.
AppleTV was only on their hardware until their hardware wasn't selling as well as the likes of Roku and AndroidTV by a wide enough margin. And when iPhone and iPAD sales are not what the used to be, Apple TV is on Roku, AndroidTV et. al., to increase the subscriber base to generate more money. At the end of the day, it's all about the money, not their ethos of design or experience or whatever else they claim.
The real lesson here is: the "walled garden" approach will only get you so far.