that much money passed around underground will cause corruption and violence, look at the prohibition era. It is worse in Mexico, areas are turning into lawless war zones. That being said, Colombia turned their situation around, so can Mexico.
The first part of your post is accurate. As for the second part, I'm not so sure.
War on drugs in Colombia
Military helicopters continue to scythe over treetops in the Colombian jungle and hundreds of millions of dollars are still poured into the fight – but there is a growing conviction that it cannot be won.
It may evolve and change shape, move from jungles to cities and from bloody battles to discreet bribes, but it will not end with a flag planted in the ground and victory declared.