The idea is to do away with the dealership for anything not related to the actual transaction (they handle financing efficiently, etc.)
Instead, the system relies on individual agents who have parking lots of different cars within a category and across brands. If I were a mid-size specialist, I'd be very family-minded and feature the Accord, Altima, Impreza, etc.
This would allow a customer to make one stop to cross-shop, and they get highly specialized counsel without any (obvious) incentive to sell hard on a certain brand.
The agent then hands off the buyer to the dealer with a fair price negotiated (using various online tools) and the buyer just closes the deal. The agent gets a cut of the sale Cars.com style.
Granted, it's not a highly scalable business, but it could be a worthy self-employment idea (with the upfront capital to do it, or loaner cars from dealerships), and the customer experience is vastly superior.