I would imagine at some point they may bake it into the car and not have it as an option - so maybe add $500 or $1k to a car, and include the FSD like they do autopilot. I don't know the math (or maths, as they say across the pond) but let's say FSD is still $10k, and one out of 10 people buy it (I have no idea) - so Tesla generates $10k out of 10 people. Or they charge 10 people $1k each, and they get the same $10k. Or what if one out of 20 people buy it? they would then come out twice as much ahead if they charged each of the 20 folks $1k each.
As I have no idea of the adoption rate, and if it strains their servers having additional cars adopt, I have no idea of the metrics, but I can easily imagine it just being padded into the price of all new cars - I mean, they all have the hardware anyway, so as far as I can tell it's a flip of a software switch.
Another option - since Tesla just raised the S and X $5k, and the Y and 3 $2k, and nobody blinked, what if they do it again, and this time include FSD.