Demand will never wane. It is human nature. It's like yelling really loud "stop being hungry humans!" (well kinda, hunger is not a good analogy but the opinion is that drugs are a fundamental flaw with our human design. Just asking to stop does not work. Also, jailing those who do doesn't help any either.
The attack has to be financial. Outsell them. Legalize, tax and monitor. Make it a health concern not a law breaking issue. If it is no longer profitable to export, cartels will hurt and weaken and that is how this very powerful organizations are taken down. Take their money away.
Why is bread bad for ducks?