The drug war exists because of two incompatible groups: those who want to use drugs recreationally, and those who want drug users punished by the state. Your argument is that if the first group would give in the WOD would end. That's true, but guess what: it's also true for the second. So by your own logic supporters of the WOD bear just as much responsibility for this tragedy as drug users.
I'd slightly recharacterize the first group: it contains two subgroups: (1) people who can be convinced to try and use illegal drugs; (2) people who will, if there's enough money in it, go through the risk of convincing others to use drugs and supplying them with product.
I know of no way of eliminating subgroup (1). As for subgroup (2), just about anybody will do just about anything if there's enough money in it.
To put it another way, the fundamental drug users exist is that human beings are corruptible. Unless one can change the nature of humanity, drug users will always exist.
Therefore, eliminating problem (1) is no more plausible than eliminating earthquakes.