> While the passenger is at work, the self-driving car will be giving rides to other people, or delivering packages and meals (not parking or driving around empty).
Says who? I certainly don't want random people inside my car when I'm not around. Don't really feel like having "For a good time call 867-5309" and a drawing of a penis gouged into my center console, and having the seatbacks tagged with magic marker. ("We're sorry to hear that, sir. We have credited your account with a $25 credit for your trouble.")
130 million people drive to work every day in the USA. Something like 115 million cars. There are maybe 200,000 taxis in the USA. If we put 1 million cars to work, we've still got 114 million sitting idle, or rather, doing loops around the block because it's cheaper.
> Greater car sharing
Says who? You can already carpool and have ALL of the advantages of a self-driving car, it's just Larry driving the car instead of Waymo. But as everyone on HN will tell you, they don't want to carpool, they want to ride alone. Riding with others is what poor people do.
You also have the economics totally backward. Your assertion is that driving will be better in every way - easier personally, less congestion, cheaper parking - and as a result, there will be less driving? Utterly backwards. Make something cheaper easier or better, and we use more of it, not less.