Much like with cigars smokers, people who smoke pot regularly appreciated quality. If it was legal to do so, and you had the time, sure you could grow small amounts of kind-bud or whatever to feed your own habit, but by in large part most people, being creatures of habit, are probably gonna tend to buy the name-brands that would pop up if it was sold legally with a adult prescription or under heavy State and Federal regulation (like acohol). Since the cost to produce the product is so inexpensive, most of the cost would be a windfall for the government. Money that can be used to help treat recovering alcoholics, drug addicts, the mentally-ill, and those who lack basic health insurance.