How would controlling the border increase drug profits to cartels?
Restricted supply hence much more expensive drugs are what we need to reduce consumption. I think I took a class about that effect once. The limiting case is infinite price and zero consumption.
Street drugs are already seeded with fentanyl and that's killing people. And bad meth. About 700 OD deaths per year in San Francisco. THAT's the misery. Dying is the ultimate being screwed.