There's really no need of them in the Post-Internet era. As the author observed in the article, consumer Joe received best deals in the comfort of home by browsing through the Internet. Car dealers also benefit from the fast move of cars, therefore they would rather sell the car at/below invoice than letting the salesmen sell them at inflated price.

This is the same with many real estate agents. They used to monopolize the market by monopolizing the information. The DoJ just ordered the national Realtors association to share the information with the public.