How is it that Apple adds features per major software update with minimal effects to battery life, but loses performance (and eventually support) over time? Some theories I've had theories over years about optimization sand such from Apple engineers, but how does that translate to devices maintaining similar battery life over the years if more processing power is needed to run the more complex updates? For example, an iPhone is supported for 4 years, maintains similar battery life (with subsequent minor updates fixing potential battery drain), and is then no longer supported because it's not powerful enough. The respective iPhone's successor gets the update because it's still powerful enough to run the next software rendition, but maintains similar, if not equal battery life. Why is that?