[Fogey]

There are salesman of almost any product that have their heads up their behinds. But think about this. You are selling at a Chevy dealership and you have no idea whether the next customer will be wanting a truck or a car, a sporty car or basic transportation, a big car a small car? So you need to know at least a little about them all. But to expect a salesman to know everything about every car is too much.
I will admit that when the car is a "specialty item", Corvette, Camaro, it is to the salesman's advantage to do his/her homework. Some dealerships (VW in my experience) have specialty guys to sell specialty cars. I don't know how the commission gets split but I do know that the guy that delivers you to the specialist gets a taste.
I'm going to a dealer tomorrow to order my Camaro from a dealer where I had a truly poor salesman. I called the dealer and told them, without too harsh of criticism, that I would order a car but needed "special assistance". I think he got the message as I got a call from a very knowledable lady who I will be sitting down with tomorrow.