This... is the opposite of my experience. Friends with iPhones seem to upgrade them unreasonably often, but my (Samsung) Android phones last a loooong time. My first Samsung I retired somewhat involuntarily after 3 years so that I could get a model that would also work overseas, but the phone itself was still fine. My second Samsung (the one I got in 2016 for the overseas trip) I just retired last fall, 2024, and even then only because a job required MS Authenticator and it wouldn't let me download it to the phone. Battery life was still fine, everything I used worked fine.

I fully expect to be using my current Android phone into the 2030s.

Well your experience is maybe more based on your friend behavior than on an absolute rule.

This is the same for absolutely every manufactured goods. The same durable car model will be kept for over a decade by some people while some other opt for a leasing plan that guarantee a new car every two years. But the intrinsic quality of the car remain unaffected.

To ponder this you must consider what become of the phone they replace : did they trash it or did they have a second life with a less edgy owner?