This is a good topic Alex, and the answer lies with Jay Cutler....he is the reigning champ....It would only take a public interview/press conference where he denounces the rampant use of recreational drugs, and the prostition, porn and the party lifestyle that accompainies it and declare emphatically that they are ruining the sport of bodybuilding and it is the pitfall for young would be champions and they should stay clear away if they want to be a top contender.......He could back it up by then asking the sponsors and magazines to support him in wiping out that element from the sport.
Thats all it will take. The current generation will grumble, they always do, but the new young generation of bb's will respect him for it and take heed. Then things will change.