When I bought FSD at $10k, the difference between Model S/X with and without FSD was ~$8k at resale. I ran an analysis of all the listings on ev-cpo.com and other places. It was only a few thousand difference on the 3/Y. So, it might make sense on the S/X, but definitely not on the 3/Y. I figured ~$2k over four years wasn't bad.
And actually having a '23 Model S loaner with EAP right now, I can say FSD is currently much better than AP / EAP. It's not going to handle local driving as originally described, but it is much better on the highway and smaller roads than AP/ EAP. Maybe that will change if they bring the merged stack to AP / EAP, though. Then they might be identical.