Well, that question comes up every once in a while. Its a good question, by the way.
To get an object, a human, a car moving - we need some "foothold" for the forces to be transformed into movement. If our feet do not find a surface with good grip (traction) our legs and feet could not move us forward.
Same story for a car - if the ground would not provide enough resistance (traction) the force generated in the engine would not be able to move the car forward.
The scenario is quite simple. The more traction can be made available the more torque can be generated to move more weight.
The challenge engineers were faced with from the start of building automobiles, was how to provide sufficient traction for not only forward movement, but also for safe stopping and steering without slipping sideways.
The interaction between the tires (their surface size, rubber compound and tread design) and friction of various surfaces provides a variable amount of traction for safe vehicle operation.
Here are the main components of traction.
By the way, it is torque that moves a car - not power!