My opinion is most of these problems are caused by the owners of the dealers. I have never dealt with a MB dealer, but did take my 88 XJ6 into the Tulsa Jaguar dealer (it was part of a Ford auto collection dealership setup) for repairs on several occasions. Even though it was an old car and they did not sell it to me, I always thought the service was excellent and the prices were high but not unreasonable. The service manager always arranged to have a Hertz car ready for me to rent at the service entrance when I drove in.
However, in recent months the dealership was bought by Penske, and is being run from California, and every expense in the Jaguar sales and service unit is being nitpicked, down to questioning whether they should be paying printing and postage costs for the local Jaguar Club newsletter (which won second place in the USA last year from JCNA). Do these guys understand they are selling $75,000 automobiles? And if even one person every ten years decided to buy because of the newsletter, well, never mind....
The service department has already lost a great parts guy due to the change in ownership, shudder to think what will be next. Last year, this dealership won JCNA dealership of the year. Any guesses on chances for a repeat? These dealership owners fail to realize people buy luxury cars precisely because they want to own luxury cars, not because they want expensive cars that are a miserable experience. Nickling and diming each customer and treating them badly is a sure way to stop any repeat business.