if the government can find a way to tax, regulate, and profit from its production, it would already be legal. However the network of growers, importers, and suppliers is so well built already, the number of those going legit and paying taxes on sales would be very low.
why do you think the government is so worried about taking down big operations inside the marijuana growing community, if they can do away with enough illegal networks pushing it, then they can subsidize it and rebuild it profitably under their watchful eye.
maybe im just paranoid from smoking too much..
oh and if you wanna know where the next big economical boom will come from in the united states, keep an eye out for church and religious organization tax, they have enough influence in major government, somebody will put 2 and 2 together and say hey, if we are passing all these laws based on religious beliefs and morals established by you, then you should pay fucking taxes to support our operations..