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.
The annual incremental release cycle is fine—what’s silly is thinking phones need to be upgraded every year.
Try that and monitor your quality of life. See if you can avoid therapy.
It's not that people think they need to upgrade their phones every year, or two, or three. It's that the phones are designed for short usable life on hardware side, and on software side, neither first-party nor third-party developers give a damn about performance.
My wife just got to a place where her iPhone got unusable because it's running out of space - mainly having to do with her massive Messages history and photos/videos. We didn't even know until I checked, her phone is the iPhone X which was released 6 years ago and technically nothing is stopping her from using it longer except the lack of desire to prune her message history/photos/vids.
My wife is someone who's not going to suffer with a poorly functioning piece of technology nor someone who is going to work hard to optimize it or prolong its life, so the fact that her 6 year old phone works just fine is a good sign that it can, in the average case.
What is the point of me having 256 GB of storage on the phone, if the phone starts slowing down wholesale once I take 50% of it? I get that there needs to be some buffer for swap and flash magic and whatnot, but I'd thought it would be closer to PC / Windows, where everything is fine until ~90% storage being used.
That's on top of bloated software doing background magic. Can't speak for other phones and brands, but my experience with Samsung flagships (S4, S7, wife's S9, now S22) is that the camera and gallery app are bloated, and their performance degrades rapidly with the amount of photos you take - around 50% worth of storage is when camera starts having delays on the order of seconds, interfering with its core purpose of taking photos.
(And it's not that it couldn't be better - Samsung just isn't investing effort in making core system apps performant enough. It's hard to find efficient apps these days on the Play Store, but there are rare exceptions, like e.g. Aves gallery, which is FLOSS and manages to be leaner, faster and significantly more feature-full than just about anything else, stock or third-party.)