In an ideal world I'd imagine pop-up touring shops where you can test drive cars and order them at a kiosk on-the-spot. A test drive circus! Ha!

Giant already does this with bikes, in my area. They rent out carpool lots in low periods (weekends, basically) and people come from all over to check out their bikes.

Sure it's a little less instant gratification, but I wouldn't mind waiting a couple weeks for a Mazda pop-up to come by if it ends up being cheaper than a dealership.