Edit: If the average garage is 250 sq ft (pretty small), average cost of real estate is $100/sq ft (pretty low), then this is a $1.25 trillion windfall. Not bad for a small side-effect of autonomous cars.
I know Google has magical fairy powers, but last I checked, a self-driving car is exactly the same size as a regular car, and takes the same storage space.
But owning a self-driving car sounds pretty sweet as well. Not only will you be able to get the status symbol car you want, you'll also be able to leave your stuff in it (without paying extra to rent it for times you aren't driving). And it's better than the cars of today! You don't need to worry about parking! You can drive when drunk or tired! You never need to worry about your cars-as-a-service being unable to send you a car during peak times!
Cars are popular to own today. Self-driving cars would be more valuable to own than normal cars are today. You have to imagine immense benefits to cars-as-a-service for it to displace most of the market for self-owned cars.
Square feet of livable housing is cheaper than that in most of the country.
Undeveloped land probably mostly sells for less than $0.10 a square foot (that's still high at $4000 an acre). But that's partly because large sales of relatively isolated land will dominate the acreage transferred.
Has it even occurred to you there might be any possible cons to your scenario?
First of all, the lot the cars come from is going to require real estate, so subtract that from your windfall. Where will they be at night or other low-use times?
Second, subtract the additional resources in gas/electricity it takes to get to my house from god-knows-where it came from.
Third, subtract the time I'm waiting in my driveway with the kids screaming and my wife in labor for a car to show up from god-knows-where. Or else the premium I'm paying to get ahead of the other guys in the queue. And while we're at it, all of those times that I wanted something from the store 5 minutes before it closes? Guess what, if I can't get a car in time, that's lost productivity. Have to buy lunch from the cafeteria b/c I couldn't get to the supermarket. Unless you're telling me that in order to accept this vision of the future, I have to be perfect and plan everything. Telling me in the future no one will be able to get to the store 5 minutes before it closes is just unrealistic, undesirable and unacceptable.
Fourth, subtract again, the additional energy needed to take the car to its next destination.
Fifth, consider all of the extra cost of adding, servicing, verifying, maintaining LIDAR and servoes to all of these millions of cars. With thousands of dollars of extra parts, they're going to require thousands in extra maintenance, inspection, training and insurance. Yeah, I know that's boring. It's not an interesting technical problem, but that's the reality of motor vehicles. If anyone thinks this won't make the price of vehicles go up significantly, they've never been in charge of anything critical.
I'm not "against the future," it's just that all of these digit-heads are seeing a grandiose signal-processing problem and doing multiplicative math like yours to make it look attractive and not even operating at a practical level whatsoever.
But don't be surprised when the majority of people refuse to pay 100% of the price for a vehicle they only use 3% of the time.
Going that direction ... Did you know? A typical microwave oven uses massively more electricity simply powering the LED clock compared to the amount it uses actually cooking food.
So, if it draws about a kW in use, that means that if you use it for less than 130 seconds per day, or just under 2 minutes, you'll actually use more power on standby than on cooking / heating.
I think I use my microwave more than 2 mins each day, but there are days I don't use it at all, so I'm not sure how it would even out.
Where I live (Berkeley), and in the Sf Bay Area in general, car as a service would be remarkably effective and popular.
The real estate costs can be extremely low for self-driving cars. Imagine a tower of, say, 10 cars stacked vertically with an elevator mechanism to bring them to and from ground-level. Since each autonomous car is interchangeable, you can just treat the vertical parking lot as a stack. When demand is high, pop off the stack. When demand is low, push back onto the stack. No need for ramps or anything else that existing parking garages use. And just to be totally clear, humans don't interact with this tower, it's just a storage mechanism for empty cars after they've unloaded passengers.
It's certainly true that most cars spend most of their time being parked and unused. But they tend to do so during times of day when there is very low demand. The vast majority of cars are unused at 4am (and, indeed, at 2pm), certainly. But even if every car that was on the roads at 4am was shared, that doesn't increase utilization of the car-pool very much. And you have to be able to handle the routine car-use spikes around rush hour.
Pod-based transport would also make public transport easier and closer to a door-to-door experience.
In any case, I don't think that that's a feasible option for the majority of jobs.
Right now, my wife and I have two cars. One of them is only used 2-3 days of the week. The other is only used for a small portion of each day.
If taxis weren't needing to cover wage costs, I'd already be better off switching from the second car to using a taxi to get to and from work. Registration, insurance and servicing for the second car is $2-3k/year.
If your costs for the second car are more than $1k in just registration and servicing are more than about $500 a year, that, first, suggests that you're not very cost-conscious today. My car's cost service and registration fees are much less than that. Second, service costs also are basically a per-mile fee -- your car's quality doesn't degrade when it sits in your garage, and you'll pay the service costs of a vehicle you use directly or otherwise.
You didn't mention fuel, but of course again that's essentially per-mile, and costs what it costs regardless of the car ownership model.
That leaves registration, which is a small cost, but would be shared in a shared ownership model.
Now, of course, the actual major expense is the cost of buying the car in the first place, defrayed over the lifetime of the car, minus any price you get for selling it. The big advantage of a car-share service would be that you could share that cost with others. If a driverless car costs $50,000 (and we have no idea how much they would cost), and you use it for only 5 years, then sell it for $20,000, you get $6k per year. In a shared ownership model where you share it with three other people, and the company that you're going through makes about 10% gross margin, you're looking at $2.2k instead of $6k, so yay, savings of $3.8k per year. That's a lot of money.
If, on the other hand, a driverless car costs $30k and can be sold after five years for $15k, then it's $3k per year to own and $1.1k per year to rent, you're saving $1.9k instead $3.8k, and that's still not peanuts, but you suggest that right now you spend more than that for a not-very-highly-used second car. The advantages of owning are considerable.
You could imagine that in addition to single-serve autocab services, you could have auto "micro" buses, sitting 4 people. Your "bus" is guaranteed to stop at no more than 7 other stops. With tens of thousands of people using the service it should be possible to pick optimal batches of people for each bus, to minimize how far the bus has to deviate from an ideal path for any given rider. It would be a giant logistical problem, but I think theoretically you can get a service working that was almost as seamless as an autocab service. Would be interesting to work on.