I suspect the statement comes from comparing Mercedes, BMW and Volkswagen/Audi to Ford and GM, who are no longer considered the powerhouses they once were. GM’s Handlung of Opel is in fact considered a part of why Opel was the sick man amongst German manufacturers.
Now I know it’s not concrete, but it wasn’t my claim. My only claim is that Germany’s health care, vacation and work week norms ensure that I have no desire to return to the States.