At each renewal of a range, the value offered by Cupertino for the old models is indeed in free fall. Thus we see that the iPhone SE (2nd generation) is trading up to €165 (compared to €185 when the iPhone SE3 was released and €190 in September 2021). The iPhone 12s are doing the best in terms of next to with the iPhone 12 Pro Max taken back up to €570 (but it still loses in a few months, since it traded at €645 last spring and of course at its highest at €715 last September). And it’s likely that adding the iPhone 13 to the program will drive prices down even further!
On his side, the iPhone 11 Pro Max went from €465 (September 2021), then to €425 in the spring, compared to €415 today (the smallest drop). However, expect some price surprises. Currently, it is thus possible to obtain up to 160 € with an iPhone X and even up to 185 € for the iPhone XR, or even 205 € for the XS.