Yup, that's the way I see it. I've got a sports car for summer, a Smart Car for daily commuting, and I rent or borrow a truck when I need to haul or tow something.
I can easily justify the cost of the rental for the truck, by the gas I save not commuting with one or doing the maintenance on a 3rd vehicle that just sits.
A VP at GM that did a speech had a slightly different vision. They were planning on using small electric two man vehicles that you "rent" for commuting and traveling. All automated, so if you need to carry 4 people, 2 vehicles show up at your door. Instead of a vehicle being used 2hrs a day, it would be used up to 20hrs. Connected to a server, it would know where parking spots were available and park itself (up to 30% of fuel burned in the city is looking for a parking spot).
You could also have automated tow vehicles, small diesel engines, or electric that trade-off for charging. Call for a tow vehicle at Home Depot, load up the lumber, it takes it home for you, then is reused by the next person.
A little more communistic than I would prefer, since you never "own" the vehicle, but efficient from a transportation standpoint.