This depends a lot on what the intended effect of the law is.

The cost of risk externalized by one person speeding is about the same, modulo driver skill and location and whatnot; it is not very sensitive to rich the driver is. If the goal of the law is to impose enough additional risk of a fine to compensate for the externalized risk, then it makes perfect sense that millionaires don't need to obey speed limits--as long as they can pay up.

If the law is intended as a deterrent, this obviously isn't working.