The required runway length for take-off depends on both the distance required to stop the aircraft in case of an aborted take-off and the distance required to reach a safe height over the runway end in case of continued take-off after engine failure.
A low v1 speed means that the stopping distance in case of engine failure will be short, but the continued take-off distance will be long as the aircraft must accelerate longer with one engine out. A high v1 means the opposite. The v1 speed where the stopping and continuing take-off distances are equal is the optimum v1 and will give the shortest required runway length (the "balanced field" length). Clearly both v1 and the required runway length will depend on factors such as aircraft mass, weather and runway conditions...
Thus the important thing for the pilot is to ensure that the actual runway length is at least as long as the required runway length. There is no need to change v1 depending on actual runway length.
That is not to say that you couldn't change v1 if the runway is longer than the minimum required but there is usually no reason to and I don't think pilots generally have the performance data to do such calculations.