It's the same as anything, a dealer can ask for as much as anyone is willing to pay for it. I don't think its necessarily unethical either, if would be unethical is it were, say, medicine. If someone has 90K and they are willing to drop it for a car, that would normally sell for 40K, whose going to tell them they can't?
Let me know if you find an ethical car dealership. I have a bridge for sale in Brooklyn you might be interested in.