I believe psy is referring to narcotics consumption decriminalization in our country, it led to less addiction/consumption and higher price.
As a matter of fact I'm talking about The Netherlands and Portugal. Weed bought to a street dealer in any of the 2 countries costs half-price or less of what it costs in a dutch coffeshop.
Illegal != Expensive
I guess people like 420 prefer to believe urban myths than life experience...