Drugs will undermine the central philosophy of sport  The show and the celebration of human physical achievement is what makes sport enjoyable to the public. The reason people enjoy sport is because it is a demonstration of what other fellow human beings can achieve and what humans can achieve collectively, as a species.  A spectacle is designed to amaze. It doesn’t need to be human achievement to be amazing (no one would call monster truck driving a sport). So, when humans start taking drugs to improve performance, it is no longer a sport, it is a spectacle, because there is no human physical achievement, but instead a chemical achievement.  It also becomes a celebration not of human physical achievement, but of human intellectual achievement, of who can design the best drugs. Even with fancy running shoes, we are still celebrating human achievement, which will not happen once you take it to the extreme of allowing drug use.  This doesn’t benefit athletes in the long run. Athletes won’t be celebrated but scientists will!