Friends, they are in the business of building and selling NEW cars. They realize that trading vehicles is a necessary evil so they do it but they don't want to do it at a loss. In case you haven't noticed they don't run a used car lot so all the cars they take in on trade are transferred to another seller to process. By definition they have to make something on the transaction. NOBODY will buy your used car for a retail price except a private party. It doesn't matter if you drive your brand new Porsche off the lot and then turn around and tell the dealer you want to sell it back to them - that dealer is going to tell you your car just lost 20% or more. It's the name of the game. If your car is so valuable, craigslist or any one of several web sites will solve your problem and you will make more money anyway. Don't disparage the dealer or manufacturer, you know what you're dealing with, just admit it and either take their offer or sell it yourself.
And by the way, I traded my first MS for my second MS - and Tesla's offer was $11k below my minimum. I listed the car on Panjo and sold it in 3 days. I also listed it on Craigslist and another site - had 6 others lined up just waiting for the first guy to back out (but he didn't). And I put that $11k in my pocket.