As long as the rewards for cheating outweigh the penalties for being caught this will continue.
A life ban from all sports for anyone found using performance enhancing drugs is the only way forward.
Or completely legalising it.
Since putting people in prison doesn't stop them using drugs for fun why on earth would anyone think that banning them from sport will stop them using drugs to gain money and prestige.
Legalising it will make teams and doctors responsible for the administration of it. Try getting an insurance policy or professional liability indemnity based on the fact you're going to turn the blood of your key assets into jam.
Just as the criminalisation of street drugs enriches and fuels high levels of organised crime and vast sums of money but mainly affects the low-level user, the criminalisation of performance drugs allows teams and doctors to keep their hands officially clean while athletes run the risk of using them on a nudge and a wink.
BTW, Rebellin won Fleche-Wallone last week too.