Personally, I like soft "rugs" the best. Shag rocks. Currently, that is the case, just as it was during alcohol prohibition. Most of the alcohol during that time was made domestically, not imported. But who would be growing this mar1juana if they could simply go to the store and by a pack of "dokes" (Steven King reference)? Sure, there would be a few people who would want to grow their own for financial reasons, just as there are a few people today who prefer to brew their own beer or cook their own moonshine. However, the VAST majority of the demand for drugs is adults. If their demands are fulfilled, there will be almost no reason for people to grow mar1juana in order to sell it to children. The market would be too small and the risks too great, particularly if selling to kids got you a year IN jail for a first offense, five for the second, and 10 for the third. The majority of the people growing their own mar1juana would be doing so as a "specialty" grower, much like the micro-brew beer we have now. As long as we regulate and license those people, they will have no reason to go outside the bounds of the law by selling to children. Look at Holland. Their rates of adult usage are comparable to the US, but rates of teen usage are half what we see here. Just as you would in a regulated market for pot. mar1juana would just flat work better in a regulated market. I can appreciate the hesitancy in regulating the drugs that have a high potential for physical addiction like heroin, cocaine, meth, and the like. Opposing regulation of mar1juana given all that we know is simply spitting in the face of logic and reason.
The reason you don't have that many bootleggers today is that the swill brought out isn't as good as the can you buy at the store. Black markets after legalization would face a quality disadvantage because the "good stuff" would likely want to be sold for the larger market. Most kids with limited incomes would likely buy fake weed thinking that they're getting the real thing. Decriminalizing/legalizing mar1juana would shorten that network and close channels for those also selling hardcore drugs. Because the penalties are harsh, risks of dealing with mar1juana are nearly the same as dealing hard core drugs, so the dealer has much much more to gain in rewards by leaving the possibility of dealing both.