The last iPhone I bought was a maxed-out 7. Tell me one good reason why I should buy a XS (or a bulky XR).
In addition the OLED screen is night and day: you won’t want to go back if you switch, but I’d say that isn’t a reason to upgrade on its own unless you aren’t happy with the current one.
All that being said, like others here I too would prefer an iPhone SE form factor with similar specs. Maybe they will get back there but I imagine it will take a long time for the battery and screen and performance to all fit back into the smaller size.
I bought the latest XS max because I wanted the bigger screen, faster phone, and nice oled.
Instead of focusing on what really matters in terms of developer productivity.
This is a much better explanation to slowing iPhone sales than people complaining about the missing head phone jack, the lack of TouchID, the notch or sizes. I don't think any of those design decisions have made any significant number of users pick Android phones when upgrading.
For most of us, there's simply no reason to upgrade from the iPhone 6 or 7, they're absolutely fine, and I'm not sure that the improvement in the camera quality is something that many will notice.
I'm not sure if this is the case in the US, but most carriers here don't have a 2 year upgrade plan, you don't get "free" phones anymore. You can get a payment plan, where you pay of your phone over two or three years, but they aren't getting you a new one, not even at a reduced price.
If you don't care about any of those things then save your cash and don't upgrade.