Exactly. The original reference was to prohibition. When prohibition ended did organized crime go away? The answer is no. When dope gets legalized the criminals will switch to running hard drugs. If they legalize hard drugs they will go to trafficking something else. It is what they do. You will have fewer users in jail for dealing, but you will still see people in jail for the property crimes associated with needing to buy drugs, but being too busy using to hold down a job.
There are many in federal law enforcement that are interested in seeing the effects of dope legalization because it is the cartel's cash crop.