Drug cartels, as terrible and inhumane as they are, operate very efficiently and have excellent business models. They understand the supply and demand of the drug markets and how to make the highest profits possible for themselves. They also understand drug laws in the U.S. and how to use them to their advantage.
There are enormous benefits that could be realized by adopting an Open Borders policy. The economic benefits are the most obvious. GDP growth would boom and poverty rates would fall drastically. But basic freedoms like the freedom of association would also be expanded.
Legalizing drugs would cut into the power and profits of the Mexican drug cartels. Their businesses would fail due to the greater competition they’d experience producing drugs. Drug smuggling would no longer be profitable, and the cartels’ side projects, like human smuggling, would take a hit.