Oh wait, you say they don't make money from alcohol or tobacco? Now I wonder why that is.
It wouldn't be because a criminal black market can't compete with a well-regulated legal market, would it? Nah!
I take it you've never been in cartel controlled areas of Mexico. Indeed, the cartels are in the alcohol and tobacco distribution business - two of the largest confiscation of untaxed tobacco products occurred along the Mexican border as entire containerloads of counterfeit cigarettes bearing fake tobacco tax stamps were intercepted, bound for the highest taxed areas of the United States.
And I honestly wouldn't trust any popular hard liquor in cartel areas unless it was a rather unusual brand/flavor. In some parts of Laredo, it is shocking that the cartel moonshine hasn't killed anyone.
The problem isn't what is and what isn't legal, it is the corruption that gave birth to the cartels. And they will constantly expand their influence and hold over cartel controlled territories until they are exterminated.