Errr -- SURE, but..
No doubt the price of a kilo of cocaine would also drop if it were suddenly a legal substance. Illegality does increase margins, but the rigors of operating under such conditions probably won't appeal to many. That's not quite the silver lining you suggest --

-- if the effect of 2257 is to put us squarely back where we (and numerous other legally embattled industries) have been before -- hanging by a thread that is maintained by a tiny handful of "bandits" who have balls enough to risk everything for the upside. I'd rather see an adult insdutry where 1 million people make $100,000/year LEGALLY than one where 100 people make $1 billion/year ILLEGALLY --
j-