Since the 1800s, big government has been enabling gang monopoly over the drug market(not to mention the human flesh market and even the gambling market in some places).
In order to understand why this is the case, one must understand a basic tenant of applied economics. As long as there is a reasonable demand for something, someone will ALWAYS arise to meet that demand, so long as there’s a profit to be made. When there is a demand for something illegal, only a certain type of businessman is willing to forgo the risk of violating the law and the social shame associated with running an illegal business. That type of businessman is the violent criminal, and he will run his business accordingly. Anyone who wants to compete with him must also employ the same business strategies. Criminal businesses aka gangs arise, and enjoy massive financial success thanks to the government, which protects their monopoly on the market. The only competitors are other gangs. If you want to end the violence associated with something like the crack or prostitution business, stop protecting the gang’s monopoly on the business and allow normal businessmen to compete with them. A normal businessman competing with the gang will say things like ‘you don’t have to kill someone to get a job in my crack business, you have to have an accounting degree’ or ‘I’m not going to rape and kill your sister if you don’t pay me back the loan I gave you, I’m just going to sue you’. Naturally, the gangs will be either forced to reform their business strategy(inevitably ending violent tactics) in order to compete with the regular businessmen, or will simply disappear.