https://www.cnet.com/tech/mobile/should-you-upgrade-to-iphone-14-how-it-compares-to-older-iphones/
Almost everyone wants to have the newest of something.
However, an older phone should still be almost as good as the newest.
https://www.tomsguide.com/news/iphone-14-vs-iphone-13-benchmarks
Sometimes a physical update might not be necessary every year or so, as long as the software can still be updated.
But the sooner a person can buy a new phone, the more billions of $ can be made.
https://www.computerworld.com/article/2604020/the-evolution-of-apples-iphone.html
https://www.iphonelife.com/content/evolution-iphone-every-model-2007-2016
https://www.phonearena.com/news/Apple-iPhone-history-evolution-every-model-list_id98169
https://www.bankmycell.com/blog/iphone-evolution-timeline-chart