That's not what is taken into the calculations, Vr is the MINIMUM speed to START the action that results in rotating, you must stay on the rwy till the A/C is under control then rotate.
Now, that's a tad different to what the design stuff has to say on the matter .. can you cite some authoritative references for your statement ? Alternatively, one could run with the more standard thought that Vr is chosen to achieve V2 for the OEI failure case. If you delay the rotation, you will exceed V2 and the numbers game gets a bit messy. (Irrelevant for the FAR 23 case).