If what seperates the greatest athlete in your state and the best in the world is 1 percent in performance, and steroids add 5 percent to performance, no matter if your the best in the world natural, the best in your state will still have a 4 percent advantage.
Granted these numbers are coming out of thin air but you can understand the math. The difference in performance between 1 athlete in a million and 1 in 7 billion natural, is much smaller than the difference between an athlete that is juiced to the gills and one that is natty.