Many gangs are the black-market equivalent of corporations. They are economic and social entities that have evolved to profit in illegal markets. Unlike ordinar

Many gangs are the black-market equivalent of corporations. They are economic and social entities that have evolved to profit in illegal markets. Unlike ordinary corporations, they cannot resolve disputes with courts--so they use violence. Unlike ordinary corporations, they cannot prevent theft by calling the cops--so they use violence. And, of course, because they're already facing very high prison sentences if caught, the marginal cost of committing additional crimes is lowered. Removing a giant market for gangs wouldn't just send gangs to work in other markets. Many of them would go out of business. This is precisely what we saw during the time of Prohibition--entrepreneurial gangs took advantage of their new market opportunity when alcohol was made illegal. They went out of business, or their power was greatly reduced, when Prohibition ended.