The drug addicts would either die out, or they would get tired of life in the gutter and be motivated to get off the drugs. Meanwhile, future potential drug addicts would look at them and have a higher chance of never trying drugs.
I don't know if that would work with today's drugs being more addictive than drugs from before the welfare state. But there's no chance of decriminalizing drugs working today as long as our welfare state removes some of the natural consequences of being an addict.
Well said. As long as there is someone to rescue them, they will not change their behavior.