Production by cartels outpacing interdiction by law enforcement isn't nearly as convincing as an argument for ending WoD activity. On the contrary, it's something that WoD hawks can point to and say "See? We need more [crazy expensive/attractive-nuisance-for-thugs resource X]!"
Modest proposal: The U.S. needs a Manhattan Project for weed/coke/heroin poppy production. Legality of demand isn't required; production just needs to completely undercut the market value of weed/heroin currently imported to the U.S. (or exported from Afghanistan, for example).
Beats subsidizing corn for ethanol, at least.