I was half listening to the Q3 earnings call, but I thought I heard an intriguing question about owners who purchase FSD having that option tied to their account rather than the physical car. More like a software license (which is what it is) than a physical bit of kit. Think about the value of FSD on a high-mileage car that is near the end of its battery life. When you trade it or sell it, the FSD, if tied to that worn-out device, has depreciated along with the worn out components to the point it's nearly worthless.
But if you could move it to the next car, it has kept its value and might make you more likely to replace an aging car, knowing that you don't have to buy that very expensive option all over again.