I think Apple would be better served by re-introducing a line of smaller phones. Whether it is for physical or functional reasons, not everybody wants to outdo the size of the previous model. Bigger isn't always better. People with smaller hands, young teens or smaller stature adults, would love an appropriate sized phone.
The only reason to get an iPhone Air seems to be to show off that you have an iPhone Air. Otherwise, there doesn't seem to be any practical reason not to get the iPhone 17 Pro if you have an extra $100.