I have to disagree with your analogy. We also took the leap of faith and dropped them. Then their zealous rep went over my dead and straight to the DP to offer to "survey" my customers. I actually had customer complaints from a gal named "Cinnamon" calling my customer asking "This is cinnamon calling on behalf a JL REED. May I talk to the person who does da car research?". our dealership name is JL Freed. They really turned my customers off. Then they came in with proof showing me that autotrader was the number 2 source. They seemed to dismiss the fact that customers might actually visit more than one site.
My problem with AT isn't that people do not visit it, they do. As many have said, they use backhanded, gestapo techniques lure dealers into overpaying. they use reps that are too pushy to sell their product and oversell. When their is an issue, they blame atlanta. Rather than a charging a single price for listing, they charge you a respectable amount to list, a ridiculous amount to not show up on page 20. Then decided to added insult to injury by adding a spotlight charge. Then another upsell. And to make this worse, they charge for premium listings by franchise. So much for having a strategy of stocking off brand used cars because they just wont show up. until page 30... unless it is an ultra rare car.
But back to my original reply, the reason that your analogy is wrong is that it is a not " a brand-new TV Channel: the CAR CHANNEL. All they do on this channel is show cars. "
It is a channel is an ocean of channels that do nothing but show cars. Furthermore, contrary to what they say, they are a listing site and not a content site.
I think the analogy to Roman empire is spot on. They were the big player because of their magazine. Then came the internet, and it worked for a long time. Cars.com, usedcar.com and google itself are going to continue to rise to where autotrader is/was and beyond if you understand how SEO works. Furthermore, I have more faith in craiglist than AT. I have to agree with yago on this. I thought it was a waste of time to realize how to effectively advertise on there as it isn't like advertising on other sites. Once I began adjusting, it has become a mainstay source and as yago often states.... it is free.