In Mexico, cartels are hunting down police at their homes

Wait, what? You are saying there are no cartels in enterprises where the underlying good is legal? For example, oil cartels don't exist? The cartel will exist if the existance of the cartel causes it to make more money than would otherwise be the case. You should read about all the knee cappings and dirty dealings standard oil did in the U.S. When the US had mob problems, yes the mob was involved in prostitution and gambling but it was also involved in port unloading, ice delivery, meat packing, unions, and plenty of other legal goods/activities. Many of the organized crime issues the US struggled with were related to fixing elections and paying off city workers, particularly in big east coast cities like NY, Boston, and Chicago, where loyalty to the machine meant city contracts, city jobs, etc. There was fixing of construction contracts, service contracts, garbage delivery, etc. All of these goods/services were legal.

Cartels are just organized crime, and what causes an end to cartels is rule of law. As long as there is no rule of law, it will always be more profitable for someone to break into a store and take something than to obtain it legally, and it will always be more profitable to burn down a rival company's factory than to outsell the factory by lowering your price, and it will always be more profitable to seize market share with a gun than with a better product and to extract payments by offering protection to small businesses who can't rely on the police to protect them because there is no rule of law. The idea that a country without proper rule of law can get rid of organized crime by legalizing everything they do seems pretty far fetched. The Sicilian mafia existed because of a lack of rule of law, not because of drugs. It took up drugs, it took up other activities when the opportunity arose, but it far predated them. Mexico has a rule of law problem and a corruption problem, and really a weak central government problem. Fix that, and cartels can be brought under control.

The problem the cartels will face is that there is no other business that makes as much money, and it would require a retool of the entire organization (or scale up, at a minimum) to get back to even a fraction of their power.

Cartels are not some unstoppable juggernaut: they run on capital, same as every other business. No money for bribes & no money for foot soldiers == no more cartel at a recognizable scale.

Taxation is robbery, I do not consent to my hard earned money being spent on experimental injections and wars.