Probably the biggest change to the iPhone 14 over the 13 will be the switch from 5.4 and 6.1 inch models, to 6.1 and 6.7 inch ones. This means the first sub-$1,000 'plus' iPhone since the 8+, but also potential disappointment to those who like the more compact form factor. It's widely assumed this change will be permanent, and from now on we will get the regular and plus models, but what if Apple were to alternate years between a larger and smaller than standard model? Most people now don't upgrade their phones more than once every 2 years, those who do would probably be more interested in the Pro models anyway, so this would allow Apple to target both markets with a 2 year upgrade cycle:
2021: 13 mini
2022: 14 plus
2023: 15 mini
2024: 16 plus
...
The biggest downside would be the plus being wildly more popular than the mini, as the market seems to largely prefer bigger screened devices, and Apple not being able to offer a new plus model every year. As above though, most people won't be upgrading every year, so would probably happily fall into the two year cycle on offer (or longer) anyway.
2021: 13 mini
2022: 14 plus
2023: 15 mini
2024: 16 plus
...
The biggest downside would be the plus being wildly more popular than the mini, as the market seems to largely prefer bigger screened devices, and Apple not being able to offer a new plus model every year. As above though, most people won't be upgrading every year, so would probably happily fall into the two year cycle on offer (or longer) anyway.