I think the point about the 3 year upgrade cycle being optimal unless you are a real enthusiast is right on the money. I’d say I’m moderately interested in tech improvements in this space and it seems ideal for me as I will be considering an upgrade from an iPhone 13 Pro (likely informed by how gimmicky or actually useful the Apple Intelligence stuff becomes and if I can offload my ChatGPT Pro subscription). If you’re really not a huge phone tech person or looking for the best camera quality then every 4 years is probably completely reasonable as well. At that point, the battery life is probably starting to suffer as well..
I wish we could still replace the batteries. They claim it's enclosed for water resistance, but my watch is way more water resistant with a replaceable battery than any phone is. I think it's all about forcing you to buy a new phone.