What happens when the market is regulated is that the legal sale of cannabis, which is done through coffee shops and medicinal cannabis dispensaries is not cheap and is too a high standard, because the costs associated with the production have gone up. This eventually takes over a lot of the entire market but you will always have people growing their own and selling amongst their friends. But if a guy is thinking of growing and selling and cannabis is legal, then he has to consider the wider market now. It may not even be worth growing to sell because he can't compete with the legitimate market. Eventually the legitimate market takes over completely, who grows their own tobacco ? (with the price tobacco is I am surprised it is not more popular) some people make their own alcohol but that is looked at as more of a past time/hobby and an art. Cannabis growing would eventually end up like that as well.
Set up a massive indoor hydroponic tobacco grow with like 500 plants, 2 stage set up. The look on the cops when they see its just tobacco, priceless.