But...isn’t that why we want to legalize drugs, to do away with crime and gangs?
I'm not sure who you mean by “we” but, yes, FULLY legalizing popular drugs AND not taxing them to death will eliminate the criminal element currently associated with them. That is fact with solid precedent.
The debate begins when we ask if legalization will cause more damage to society and take away more freedoms than the current failings of the drug war. There is no precedent or information that can predict what will happen.
What I do know from real field experience over 10 years is that the supply/quality of drugs has been increasing every year while prices have been stagnant. The rate of illegal drug addicts has stayed the same while prescription addicts have increased. We have given up more and more of our financial, privacy and property rights in the name of this war. We continue to spend billions with absolutely no results to show for it.
I'd say it's time to try something else and ignore the special interests that wish to keep the status quo (LE, pharma and big gov’t).