Wake up and smell the coffee, as our American cousins would say. MB aren't competing at the top end of the market these days. They're a "premium" mainstream manufacturer, competing with the likes of BMW and Audi - so they're selling cars at prices barely 1.5 times that of the Ford/Vauxhall horde. The days of hewn-from-solid over-engineering are long gone, and the marque's god-like status has been demoted to that of a mere mortal.
However, the general public still places the three-pointed star on a pedestal, and having recovered from the shock that they can actually afford one these days, they then expect it to still be some kind of paragon of integrity. In reality, it's just a mass-produced car, built to production tolerances perhaps a little higher than the norm. MB can't afford to go around pandering to every crank's obsession with a barely audible squeak. I'm amazed they've indulged this case as far as they have.