The battery drain screams of planned obsolescence. But there is always the possibility that it’s proprietary hardware just requires them to write code that just obliterates our battery.
I doubt Apple is deliberately adding bloat to iOS, but every major version is definitely heavier than the previous one.
This argument doesn't make sense from a logical point of view. If all iPhones eventually crawl to a halt because Apple ruins them with software updates, why would that push people to go buy a new iPhone? Wouldn't they look elsewhere?
Not everything has to have a malicious explanation.