Alas, let's not pretend that the 'good guys' (at least the americans) want to solve the drug problem. It results in lucrative profits that can be kept off the books and fed into various "programs", and has also led to the establishment of a massive bureaucracy that will be hard if not impossible to dislodge.
Someone else mentioned the movie Sicario in this thread. It's pretty bad in terms of plot, but one line comes to mind: One of the characters that plays a CIA agent says: "If only 20% of the population could be pesuaded to stop smoking and snorting that shit..." in order to conveniently shift the blame towards the populace. As if that worked with alcohol, or cigarettes or anything that can short-circuit the pleasure/reward neural pathways.
But I'm digressing here. A bad movie does not a point make. The real CIA knows full well I imagine that legalization is the only real solution to the problem (even if it comes with its own costs) but of course the real CIA also needs endless suitcases full of dollars to fund its operations.