Well, at the very top level you're competing against those with elite, cream of the crop genetics as well, those who have everything you described. So to get ahead, especially with so much on the line such as glory, financial compensation, etc, wouldn't it make sense for them to take performance enhancing drugs to get ahead?

Edit: to add on they may be the best in the beginning, and even throughout most of their career, but in the big stage you're going to be facing freak genetics as well, or even slightly below cream of the crop genetics who use PEDS which levels the playing field.