I agree that some people are more susceptible but they can stop. It’s just a matter of deciding to do it. The problem comes when they treat themselves as a victim. They say they want to quit but they “can’t”.
If you lock them up for 30 days, they will prove to themselves and others that they can quit. But many will choose to return to the slavery they swore they couldn’t quit.
When you can't stop for your starving children and rotting body. When not even your own death is a deterrent, that is the definition of “can't”.
The person has lost all control of themselves and they CAN'T stop without physical intervention. If there is any physical possibility of getting drugs, their mind will play tricks on them to get high at all costs.
“If you lock them up for 30 days, they will prove to themselves and others that they can quit.”
When you remove all physical access to a chemical, of course they will stop. You are not giving them any physical freedom to do so.
But as soon as they get out and have the chance to get the chemical again, they often will. Even if they managed to get beyond the chemical dependence, the mind still craves that chemical for life. It is a constant 24/7 battle for the rest of their lives. They forever hear a voice convincing them to take "just one more hit" and that voice gets louder/smarter whenever they hit a speedbump in life. A true chronic mental illness for which there is no true cure.
And don't say “it's their fault for trying it the first time”. 80% of addicts get started on legal Rx opiates or stimulants. Almost 10% of people are prescribed addictive pills as children. Big pharma is the true world-wide dope cartel and responsible for most of this carnage. The WOD is mainly a program to eliminate competition.