I’m convinced that there will be ways to differentiate the riding experience. In fact, it will be the most important factor, because as you say the driving is done by a robot (the car). So, the way the car behaves, the way you connect with it, the way software and hardware work together, all of this will have a huge impact on the experience and will not be easy to be done well – and not every carmaker will get this right.
Premium pricing will also be possible when the experience is better. I can imagine to rent an Apple Car for the better days, for special occasions. There will be room for premium (as there always is).
Did you read my other pieces? I have touched many of the aspects you raised in your response. Happy to discuss further.