Won't stop a darn thing. Another just takes their place. As long as there is a monetary reward to be had, risk takers will continue. The demand must be curbed, and the traffickers will stop. Or just legalize it all...........
Your reasoning also breaks down badly when you apply it to other things, like securing the border or preventing almost any other kind of crime.
By greatly increasing the street price of drugs, the 'war on drugs' has success.