Since our cars can be upgraded OTA as new features roll out, there isn't as much of need to get the latest and greatest like an ICE.
I think this discounts the fact that there will be additional hardware added beyond Autopilot, and of course body style changes. The car can be upgraded OTA but only within the parameters allowed by the hardware. I imagine a point at which my MS will no longer be eligible for upgrades. The last one I get will be where it stays, either because of onboard processing power, available hardware, Tesla sunsetting model support, etc. It's a continually advancing vehicle beyond the OTA upgrades, so I don't worry much about the CPO market.