The first world overcame those problems by extracting obscene amounts of wealth from the third world to make their populations handsomely rich. When you have everything and lead a comfortable life you're more likely to spend your free time at the pub than go enlist with some private gang or militia. If you look at all the places where organised crime is rampant, the common denominator is always extreme poverty. People living a wretched life, unable to meet their basic needs, with no glimmer of hope for their future are just begging to be recruited into a gang for even the smallest of incentives.