If drugs are to be legalized, I presume that means advertising of said drugs should now also be permissible This happens now. Drug dealers 'brand' their drugs, especially heroin, giving them names like 'spider' or 'blackjack'. The names get around, and addicts shop for the best dope.
There are many ways to "legalize". If You take the money out of drugs, no one is going to stand on the street selling them. No one has all the answers, but the war on drugs doesn't work.