The competence and pricing of dealers along with the proclivities of a car’s customers have a lot to do with it, too. This ranking is basically “of the cars brought for the german federal safety inspection, what percentage were issued a note or failure about an item in a given category” Things like bent suspension linkage caused by driving into a curb, poorly maintained brake pads, or torn rubber boots left unaddressed would all count.

You can see this skew quite easily on these reports by looking for VW AG cars that are generally identical, and comparing their rankings, like Audi A1, VW Polo, Seat Ibiza and Skoda Fabia.

(note that this isn’t really to defend Teslas, which are clearly behind on this metric in Germany for some reason. Just; the reason could be “their service is overpriced and nobody wants to take the car in” rather than “the car is junk.”)