One of the problems with people who are in the violent gangster industry is that they are trapped there. The business which enables them to live is illegal, so its difficult to go to the police when they are forced to do things they don't like. If your competitor is providing a substandard product and undercutting your sales and putting you out of business, then there is no recourse but to shoot him, eh? In the legal world, you can go to a regulator and when he is prosecuted, he will be losing sales. Most drug takers I would say aren't really interested in funding violent gangs..

If drugs were legalised, then you might find it unpalatable that the same people were now providing the drugs legally and their past sins seemingly forgiven, but the incentive to commit violence is now a lot less, and things will change.

I don't know the history exactly, but after prohibition I bet the gangsters didn't immediately become peaceful CEOs of successful corporations.. but then after a few intervening years, the alcohol companies are no longer violent, so obviously something has changed.