A check-engine light comes on during a commute. The driver calls two shops from the car park. One rings out because everyone is in the bays. The other answers, asks the make and symptoms and offers tomorrow at 8. That shop gets the repair, and with good service, the next five years of maintenance.
Shops rarely lose customers on price. They lose them at the phone, and again six months later when nobody reminds the customer their service is due.