Ehn... not so much sad as unsurprising. It's not the cartels that are driving drug trafficking, just like it's not corporations or investors that create markets or provide jobs. It is -- and has always been -- existent demand. So long as the demand isn't impacted, volume will not reduce -- probably not even over the short run, and definitely not over the long.
... and you can't really reduce demand by imprisoning drug lords. Not meaningfully. It'll take either a very extreme cultural shift (both in the countries where demand centralizes and where production occurs) away from recreational drug use (hint: This isn't going to happen.), drug legalization of various sorts shifting production into better controlled areas, or something legal -- probably some form of designer drug, or a spread of them -- that provides a superior competing product, for less. Then -- and almost certainly only then, no matter how many cartel members you kill or imprison -- you will see demand for cartel products reduce, and consequentially cartel power begin to wane.
"How to kill the cartels" is... well, basically it's just simple economics. If you starve them, they will die. If you take away their food, they will not revive, later. If you kill the members and dismantle the organizations, all that happens is another group will grow to fill their place -- their sustenance (drug demand) is still there, and until it's not, the problem will remain.