The transition to a society of legalized drugs is a different problem from the economic transition after World War II. But the solution is always the same: more liberty and less government. Free people will sort things out because they have to in order to get what they want; politicians know only how to play political games.
We don't have to know how everything will be handled in a free society. All we have to know is that free people have much more incentive to solve problems than do politicians whose own livelihood and life savings are never on the line.