> throttle their own devices to manage power/battery trade-off?
With modern power management, the system constantly makes decisions on throttling up and down at the sub-millisecond level, balancing performance, power usage, battery lifetime and thermal constraints which affect component lifetimes. There are probably hundreds of combinations of criteria it uses to decide what to do and when.
This has nothing to do with Apple versus Android or open versus closed. All modern phone systems do this, the Android device makers face exactly the same issues. There isn't a single modern smartphone on the market that doesn't throttle the CPU in order to preserve device lifetime, because that's a big part of what thermal management is about. It's why people overclocking their CPUs are taking a risk. That running older batteries hotter and harder degrades them rapidly and risks device outages is simply a fact of physics. Painting these practices as 'planned obsolescence' is, frankly, incredibly ignorant.