Bridgestone Potenza RFT (225/45 R17) on the rear of my touring were finished by 15K miles. Never had a tyre with such a low mileage in my life. Typically I'd get 20k on the rear of a BMW. Last set of Goodyear F1, non run-flat, gave me 20k on the rear, with about 3mm of tread left when I removed them. Current rear tyres are about 14k miles and 4.5mm tread depth.
Easy motorway miles are the answer, driving on hot rolled asphalt is much kinder than granite topping, we have on much of our Highland roads.
I remember my father in law used to get over 50k from Michelin tyres, when he was driving the motorways as a technical rep.