There are a million DOCUMENTED gang members in the US. 500k are Latino/Mexican/Hispanic, 400k are black, the remainder white or asian.
There is not enough prison space for the crimes they commit, and legalization of narcotics WILL NOT put these guys out of business. They have many enterprises they engage in and drugs are only one facet.
Adding more police is not the answer either. We have at least 3/4 million people who are considered law enforcement and they are very good at bringing gang members in for crimes committed. Judges and prosecutors are equally good at letting them out.
More prisons. Only when you remove the criminal element from society do you see a serious reduction in crime.
It would put them out of the drug business. It would free up prison space occupied by non violent drug "offenders".
It's a start. Prohibition didn't work 100 years ago, it gave us the kennedys. It doesn't work today, and it's giving us ms13.