Arguably it’s the opposite of planned obsolescence - even used phones are not obsolete and are still in circulation.
It’s also worth pointing out that this is Apple’s stated policy - they want phones to last longer so that more people have them and they can continue to sell services to them.
This has nothing to do with the definition of planned obsolescence. It does not matter what people do with the old phones.
I don’t need to reread it. My response applies to design obsolescence.
Relatively few people upgrade every year these days. The fact that the old devices are still desirable negates the idea that people don’t want them because they look outdated. I.e. changes in design are not causing people to stop using the devices.
For design obsolescence to apply to Apple, workable devices would need to be retired from service early because they were no longer seen as desirable.
That isn’t happening.