The point is that prohibition increases the mean or median strength, not the maximum available.
One argument I've heard in favour of legalizing cannabis that it would increase the supply of weaker strains, reducing the potential harm to users.
One argument I've heard in favour of legalizing cannabis that it would increase the supply of weaker strains, reducing the potential harm to users.
But the basic idea that there exist powerful market-forces which incentivize the production and supply of increasingly strong products when a good is prohibited seems quite logical and supported by the evidence cited in the post.