I'd suspect the average person won't notice much difference (on the main lens) until about iPhone 11 or older, with still photos. Computational image processing

I'd suspect the average person won't notice much difference (on the main lens) until about iPhone 11 or older, with still photos. Computational image processing does a TON of heavy lifting with these tiny sensors. With video OTOH, the improvements are much more noticeable. I also suspect that is why Apple focuses so much on video as its a harder problem to solve and so much easier to differentiate your hardware from competitors.