how do you incrementally roll out "full self driving?" either the car drives itself or it doesn't...
As I've said elsewhere, this comes of using the term "FSD" to mean
two entirely different things! On the one hand, it's used, and commonly understood, to mean a car that does not require a driver. You can sleep in the back seat or send it by itself to pick up the kids. On the other hand, Tesla uses it, and some here use it, to refer to a package of unspecified driver-assist options which Elon optimistically believes will eventually lead to a full-self-driving car.
You can incrementally roll out a set of features. You're not incrementally rolling out a car that needs no driver. You are bringing the car closer and closer to the day when it will become fully self-driven.
IMO Tesla will refund money paid for FSD if begged but will invite those who did pay to apply it towards a new vehicle which is actually capable of FSD and then once those accounts are settled they will raise the price. Paying Tesla for a feature which does not exist is just a donation to the cause. Love ‘em, but dont’t trust ‘em.
There is no need for them to wait to raise the price. Elon said that the car had all the needed hardware for FSD so he cannot charge extra for the needed extra hardware. But I don't remember Tesla ever promising that the after-purchase price for FSD would remain unchanged. They could raise the price tomorrow for anyone who has not already paid for it. Once you've paid, they cannot charge you any more and must retrofit the car as needed.
A bigger question is, what happens when the cars reach typical retirement age, say ten years, and true full self-driving is still not available? People will want their money back, Tesla will give it back without interest, and some disgruntled customers will want interest.
When a farmer sells wheat futures on a crop he has not yet harvested, he is obligated to deliver the wheat even if his crop fails. So he buys crop insurance. What happens when you sell "futures" on a technology that does not yet exist? At what date can buyers reasonably claim that the delay constitutes breach of promise?