Criminal groups that bring undocumented migrants through Mexico and across the border make $6.6 billion per year, according to the UN. That compares to estimates of $10-40 billion or so for drug revenues in Mexico. I'd be interested to see similar estimates for organized crime's revenues deriving from extortion, kidnapping, pirate merchandise, and the like; I'd bet it's another several billion as well. One lesson from all this is that the government needs to improve its capability to combat the gangs themselves, and not simply attack the drivers of the drug trade. Even if the drug trade disappeared, $15 billion dollars or so is still quite enough to support a diverse band of wealthy mafias. Profit margins would be less, and the work is more labor intensive, so it would be spread out among more people and not be as prone to emergence of all-but-untouchable capos like Chapo, but the solution to Mexico's public security in the near and medium term does not lie in demand reduction or legalization alone.