> Drug violence is rarely about cartels vs cops -- more often it's cartels vs cartels and dealers vs dealers.

Precisely the point: If the cartels come to intimidate grandma, she calls the police, because her operation is legal and the intimidation is not. The police, because her operation is legal, then go after the cartel and shut them down.

Additionally, contract laws and theft/burglary laws and so on work in grandma's favor, because the legal system is at least potentially on the side of her legal operation. This alone greatly reduces the need for violence.