The beautiful thing about trucks is...you can put _multiple_ cars on the truck.

Eh... Delivering multiple cars over a short distance by loading them up on a flatbed or car hauler just doesn't make any sense. Tow trucks will always be more expensive than calling a taxi. Especially given that this is basically a textbook example of the travelling salesman problem. And I don't mean computing a route is hard, I just mean that in practice while there's overlap between destinations for a sparse set of e.g. 10 destinations spread evenly over some area around a hub it's not like being able to go between destinations directly makes it 10x shorter. Trucks are expensive to maintain and operate, much more so than a regular passenger car. Trucks also can't deliver as easily or to as many places as a person driving it. If someone lives down a dead end road that's extremely inconvenient for the truck whereas it's a non-issue for someone driving.

Car haulers don't make sense for sparse local deliveries.

Handy if you're buying multiple cars.

Just think of it as Uber Pool/Lyft Line wherein one car goes to your house, and another goes to someone else's house.

How many cars do you buy at the same time?!

And increase risk of road damage/wear in transit, which likely wouldn't be caught on initial inspection during handover.