Brake pads completely gone after 25,000 miles

At 75,000 miles, I had new brake pads put on and all rotors re-surfaced. When the car reached 100,000, I noticed some issues with the brake, so I took it to a different dealer. The service rep told me three of four brake pads were completely gone, as a result, three of four rotors were ruined, he showed one to me and it did have groves on it, and three of four calipers were seized. Only one of my brakes was working and the car was dangerous to drive. Brake pads usually last from 30,000 to 60,000 miles, correct? How is this possible? I wonder maybe one caliper was seized and the service rep tried to up-sell me to get unnecessary work to be done. Thanks!