The prices that are charged by Vancouver dispensaries are not dramatically different from the prices that are charged by the licensed producers. One could say that much of what comes out of the dispensaries is a product of organized crime, because by definition the licensed producers would lose their licences if it were known that they were supplying the dispensaries.
The price per unit of intoxication for cannabis is remarkably inexpensive. It hasn't gone up in 30 years, unlike alcohol prices. Most people don't really want the experience. People experience cannabis as youths and they tend to move away from it. Something like five dollars' worth of cannabis on the illicit market will get three people high. Good luck with alcohol, given that equation. Alcohol is simply a more desirable substance for most consumers.