The drugs would be cheaper because most of the price you pay for a drug is because of the risk the seller needs to undergo to bring the drug to you, the actual cost of making is very low. And if they were cheaper, the need for addicts to rob pharmacies would diminish greatly. And even if addicts would rob pharmacies in bigger numbers than they do now, would that come anywhere near the amount of crime that the drug mafia is committing?

In a perfect world people would be able to use these drugs without becoming addicted to them and just have the fun they can provide. I have tried almost all the drugs there are and I am addicted to none of them, recreational use is possible with any substance.