From my experience, Android devices degrade faster in terms of how slow they become; the UX and UI are less responsive and they can't keep up with newer applications.

While I agree that there is an "Apple Tax", the retained performance of iPhones is really surprising, and that's why I feel they make a good value.

Some of my folks have (as some of yours might as well) iPhones 6s and 7 which have been running with absolutely zero issues. Given that the 6s is 6 years old now, I find that very impressive.