Legalization will flood the market prices go down
Right now you get those in the market that are willing to take the chance despite legality. They will always be there if legal. What happens is those that the legal aspects kept them out will jump in therefore flooding the market with product which creates more competition which creates lower prices. Simple business class 101. Now there may be some increase in demand but not much more than you have currently. Because even if legal it would initially still be taboo therefore the demand you currently see would still be floor and ceiling of demand give or take a couple points. But legalized will bring way more product.