In this score, after all, the iPhone 15 will not be much different. The price of the new phone should drop, which is mainly to open up sales space for the iPhone 16. However, the used iPhone 15 should have a larger drop.
Yes, there will be a small drop in price of the iPhone 15 models. In fact, carriers are basically giving them away to get you to switch from your current carrier or from an Android to the iPhone.
I would argue that ‘most’ current iPhone 15 owners will hold on to it for at least another year.