> That's because they haven't came out with another small iPhone in more than four years.

I kind of agree with the previous comment. I think if you spend a lot of time on the phone, have a lot of apps then it makes sense to upgrade your phone more frequently and also makes sense to have a larger screen and better battery life. So conversely, there is a correlation between people who have smaller phones and upgrade less frequently.

I have my iPhone 12mini for 5-6 years now, and I'd upgrade it now if there was a new small iPhone. But I would upgrade it 3 years ago.