From the point of view of a maker and seller of cars, the incentive for self driving is that it increases the size of the market. Rather than just selling one

From the point of view of a maker and seller of cars, the incentive for self driving is that it increases the size of the market. Rather than just selling one car per adult in a family, it could sell one per adult and one per child. Car makers operating according to this incentive will try to discourage taxi-like functions in self-driving cars, perhaps by only allowing operation when specified people are recognized by the car (anti-theft feature!).