The original business of criminal gangs was stealing- still an entry-level raison d'etre. The Roman latifundia in Sicily, through labor-racketeering, became the birthplace of the Mafia. As the world economy matured criminal gangs coalesced around every center of money or power.
In the 20th Century, oil was the center of power. The gang structure was surprisingly similar in all the oil-exporting countries- a local oligarchy in league with world oil-buyers, using a portion of the proceeds to subsidize the workers who pumped the oil, the workers being used when necessary as Brownshirts in defense of the regime. The PRI in Mexico is a prototype example and the fall of the PRI with the maturation of the Mexican economy a lesson in how such gangs fall.
This story has no moral. This story has no end. This story just goes to show that there ain't no good in men.