What you say is true... To a certain extent.

It truely depends if you live in a conservative or liberal market area of the united states. True if you live in L.A. or Dallas you aren't going to find a car deal on Ebay that would out do you're local dealership. There's just too much competition in major markets like that.

On the other hand, should you live in a conservative market such as much of Michigan, Indiana, Etc etc. Ebay has incredible car deals.

For example in this conservative market I was able to find several 1999 S70 N/A with around 45K miles for around 18,500 But looking on ebay revealed T5 after T5 maxed our in the Boston and Buffalo NY area for less than what local dealers wanted for their N/A without sunroofs even.

Also I believe the reverse is true. If you live in a liberal market you have a lot of competition and thus if you advertise on Ebay you'll dive into some of the more conservative markets out there and might find yourself getting what you think is TOP DOLLAR in your area while the buyer thinks he's getting a DEAL compared to his local.

Again, this is all my opinion so take it for what it's worth.