Uhh....?
Wheels not locked: Dynamic friction between brake pad and brake rotor.
Wheels locked: Dynamic friction between tire and pavement.
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Key word - tire
Wheels rotating - coefficient of static friction between tire and road.
Wheels locked - coefficient of dynamic friction between tire and road.
The dynamic friction of the pads/rotors is designed to be high - when the brakes are applied the pads transfer small amounts of friction material to the rotor (majority of this occurs during bedding in). The friction material on the pad and rotor then sticks to each other, slowing the vehicle.
The other thing to remember is that comparing static and dynamic friction only works within the same system i.e., changing between rotors and tires changes systems and you can't draw comparisons between static and dynamic friction as easily.