Earlier quoted context omitted.
An improved camera can't be something applied in software, a faster chip can't be applied in software. So by your own standard every version is warranted.
"significant" is the key word here. I'd be hard pressed to think of a generational release of an existing phone line in the last 5 years that I would describe as a "significant" improvement. The things you listed (camera and chip speed) are basically the only things left that these companies can claim is better than last year's model, but only because it's so easy to use synthetic benchmarks and numbers that mean not…
For me, the addition of satelite SOS introduced on iPhone 14 is a game changer. I do enough out of cell range activity that I carry a SPOT device.
The ability for one more device (and pricy subscription) to be eaten by my phone is fantastic.
For others it might be onboard ai capabilities.
Each incremental hardware update to an iPhone tips the utility scales for someone, and is a completely ignorable change for others. Some people don’t care a bit that the new iPhone has a 2k nit brightness, for others, that is the feature they’ve been waiting for to upgrade.
I don’t pay attention to androids much, but it is pretty rare for iPhone full number bumps not to have a hardware feature that is new.