I think that 9 out of 10 "salesmen" should now be regarded as "check-out assistants".
That is to say, most customers specifically want to buy a Mercedes (in this case), so they will often go through the appauling service to get what they want. Bare in mind 9/10 buyers are "Jo Public" with no real enthusiasm for cars, driving or motoring. The car is a tool.
Similarly, I'm not a foodie, and if I get bad service in a restaurant, I let it go over my head and just don't tip. My brother-in-law is a chef and if he gets bad service he goes for it, hell for leather...
Thus, the "salesman" need only talk the custmer through the options, and take payment. Hence "check out assistant".
My theory is MB get away with paying peanuts to monkeys, because that is all they need.
There very good salemen out there and I have worked with some fantastic salemen who could sell ice to eskimos and make the Queen feel more important than herself.
It's a sad state.