Athletes are always one step ahead of the testing bodies. They use designer drugs to escape detection and most offenders are not caught.
The Lance Armstrong scandal shed light on the reality of doping in professional sport. The cyclist famously never recorded a positive test for doping, despite using performance enhancing drugs rigorously and encouraging others to do so.  The Armstrong incident reveals the futility in banning doping. Athletes will always be one step ahead and detection rates will never reflect the full extent of those doping. If the governing bodies do not have the resources or technology to eradicate doping from sport, which they evidently don’t, then they should permit doping. Because continuing on with a situation where only a handful of perpetrators are caught affords those that can dope undetected an even greater advantage and undermines the premise of an even playing field in professional sport.
If athletes are getting away with doping, we shouldn't throw in the towel and just permit performance enhancing drugs in sports. A far better response would be to invest more resources into policing to help governing bodies get ahead. The police play a game of cat and mouse with drug dealers, but they don't just accept their limitations and legalize all drugs. They invest more, develop new policing strategies and try to get ahead of the dealers. The same should apply to doping in sport.
[P1] Athletes and coaches will always be a step ahead of governing bodies. [P2] Therefore, there will always be doping in sport. [P3] Therefore, the only way create a level playing field is to permit doping among all athletes.
Rejecting the premises
[Rejecting P3] Permitting doping is not the logical solution. Increasing investment in policing and detection is.