There is so much time, effort, and physical waste that is generated by slightly redesigning phones every year purely for the sake of making sales (as opposed to meaningful improvement upon the existing design or introduction of a new hardware feature). Think not only of people upgrading for the sake of it, but all of the cases, screen protectors, and other assorted accessories cast in plastic for previous models that are garbage now.
It would be nice if we could just space these things out to 5 years or so now, because that's probably how long it takes for anything to change enough to justify a new model.
I have an iPhone 12 Pro Max that is three generations behind now. While there is nothing I have to have, the always on display, the USB 3 speed, and video out to my portable USB-C monitor on the iPhone 15 Pro would be nice.