Why is Power caused by the driving force?

Say we have a car on a rough inclined plane, the maximum constant velocity at which the car can travel is $ V $, the driving force is $ F_d $ and the frictional force is $F$.

Shouldn’t the power exerted by the engine be used to:

1. Overcome the $F$ and $mgsintheta$ component of weight.
2. Cause the car to move at velocity $V$.

Would it not then make sense that the power of the engine should be the product of $V$ and $Fnet$ in the direction of motion?

I am at an extreme loss at where my reasoning fails as apparently the power of the engine is due to only $DF$, which does not make sense to me as if the power is due to only $F_d$ would that not imply that the overall speed would be less due to the resistive forces acting on the car?