By the time Model 3 is actually available to a new buyer, the youngest Model S without AP will be 5 years old and oldest Model 3's will be 2 years old, so yes, non-P, non-AP Model S will probably go for same or less than a new Model 3.
AP is really not all that it's cracked up to be, in two years AP2 will be forgotten by Tesla (the AP2 car will be capable of FSD, but not the sensors or whatever other BS Tesla will come up with, like when they delivered a car was speced at 691hp but delivered 463hp instead and Tesla's excuse was that the motors were capable but not the battery or the fuse or the wiring). If new Model 3 in 2 years actually has full FSD, then absolutely, expect all non-FSD cars (not just Teslas) to drop in price, but that's a long shot at best. Until full FSD, AP/EAP is not going to be a large price driver, like
@kev1n and
@Olds442 said, at the current capabilities of AP1/2 there are plenty of people who don't want it or at least don't care. Heck, our latest Model S has the AP2 hardware but for us EAP or FSD is not worth it at all, so we won't pay for it until the car can drive me to the airport (50 miles), drive itself back home, park, then come pick me up at the end of the week - assuming no severe weather and that someone will plug it in when it's in the garage at home. Oh, and of course assuming we are still alive when that happens.
