My current theory, based on the Apple TV 1G and the 2G's "hobby" status, is that the hardware will remain the same for two more years. By then the iPhone 4, will be on its last firmware (7). Because the Apple TV 2 is an iOS device, Apple will stop updating it with the release of iOS 8. Then in the Autumn of the release of iOS 8, Apple will release new hardware to run iOS 8. This three year cycle will probably continue until Apple no longer deems the Apple TV as a "hobby". Of course I could be completely wrong and Apple will kill the Apple TV in September and replace it with a completely new device that poops rainbows.