The entire global taxi market is ~$250B a year.
Google made ~$265B from its ads last year.
Google made ~$265B from its ads last year.
The global driving market.
When these are ubiquitous enough, the vast majority of people who currently own cars won't need to. It'll be so much cheaper and easier to use rideshare.
If I lived in a city and garaging a car were inconvenient/expensive? Maybe. But that's not me or a lot of other people.
But if it's half the price over the course of a year? And you can summon it in advance cheaply? And it basically never takes more than 5 min to arrive anyways, since they're everywhere?
You might decide it's worth it to keep the stuff you really need in a messenger bag or backpack or something, the way people in NYC do. And maybe roof racks don't matter if you can just summon a second autonomous van behind you to hold whatever you were going to put on your roof.
Obviously if you're a contractor or something you'll need your own vehicle. But the point is that for most people, sure they can't keep stuff in their trunk all the time, but that's a happy tradeoff if the total cost of driving is 50% less.