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.
It's very rare that there are any updates at all within the same generation. Year in model designation is just "ha, look at his looser driving last year BMW" and to show when car left assembly line.
There are some examples where the same generation had a significant upgrade without a facelift, but those are rare. One example I could think of is MX-5 (ND): between 2015 and 2018 there were no changes at all, but in late 2019 there was nearly complete overhaul of its powertrain and then a small update in 2021.