While that may be true in some instances, I have seen plenty of rotors that are actually warped as a professional automotive tech. In the Honda world the 09-15 pilots and 12-17 odysseys constantly have rotors warping. The exact reason I am unsure, but I speculate it had something to do with the front and rear brakes being undersized for the vehicles. Front's being undersized allowing for a greater build up of heat in the rotors and rears being undersized causing the fronts to work harder. For the odysseys Honda even updated the rotor design for improved cooling.