There is justice only where just men rule.
I happen to think it unjust to initiate violence against the nonviolent, which the drug war does do (and gun control laws also do). From that injustice, many others flow. Of course, this being a liberal gun-safety utopia brings about its own problems, such as making a lot of defenseless people to prey upon. No one small policy change will fix everything, but what's clear is that the present policies are evil, because they result in the evil seen here. (Abolish the welfare state, and the welfare mothers go away too, for example.)
They'd be killing each other to take over something else. Protection rackets, welfare mother paychecks, anything you please. They will beat the defenseless for a living because it is the only livelihood they know
But unlike drug sales those crimes have actual victims, who will do what they can to prevent their commission and cooperate in their punishment. Drug prohibition is failing in much the same way that alcohol prohibition failed.