Correct. The drug trade and the cartels have been in Mexico for a long time. I never recall being concerned about things in the border towns until the Kilroy killing in 1989. But most of us on the border kind of wrote if off too as a unaware Gringo college student thinking he was invincible not being aware of his surroundings and just a case of being at the wrong place and the wrong time.
They didn't become the animal they are today with their fingers in things you wouldn't associated with the drug trade like shell companies to launder their money and of course the human trafficking component until the Columbia cartels suffered defeats and their leadership went down starting with Pablo Escobar. That did take American money and man power and covert stuff we will probably never know about until files are opened 50 years from now or so. The Mexican government needs to do the same where they put a face in the public they hate the Gringos and their Army of the North to satisfy their national pride, but then take the bitter medicine that if they want a country that is somewhat safe compared to the last three decades or so, they can't do it alone. Columbia still has a drug trade and network, but it's not the same as it was and that's where Mexico needs to go.
I'm not sure the cartels are all that concerned about legalization either way now as they shifted their business model as noted above. Sure they still want to control the cocaine, heroin, etc. stuff. But they've shifted hard in the Fentanyl and no telling what else is being cooked up in labs down there or in China which will become the next lethal powder.