I lived in Denver 4 years ago, and this was very much the case with marijuana there at the time. I knew a few people with MMJ cards who were recreational smokers with no legitimate health issues and they all said it was very easy to find a doctor who would write you a relatively bogus script for a MMJ card for the right cost and then you could buy from the dispensaries (it was decriminalized at the time, but not legalized). On the other hand, if you knew the right people, you could simply buy directly from the same people who were supplying the dispensaries with their weed, cut out one of the middle men, and save money. For some people the convenience of being able to walk into one of the many dispensaries any time they wanted and peruse a variety of strains of weed was worth the mark up and cost of acquiring their MMJ card. For a lot of people, weed is weed is weed, and if they could call up their buddy who grows and pay $40, they really have no reason to go to a shop and pay $50. When it comes to hard drugs with very serious addictions, I'm positive this gap would be even more significantly pronounced. You're not going to see a serious heroin addict rationalizing that they can spend $10 more and go legally buy their heroin. They're going to call up their dealer and spend that $10 more to get an extra .1g. In terms of the general discussion of the popularity of heroin, it definitely started getting more prevalent as the companies producing prescription opiates starting making them harder to abuse, and then continued to rise in popularity as a lot of the Florida pill mill doctors started getting shut down. As the pills were made to be harder to abuse, and the supply of easily abusable opiates started slowing down a bit, the price of pills started going up and for a lot of people with significant addictions, they could not afford to maintain their level of use with pills. From there, heroin was the obvious next step for a lot of people because they could get their same level of high for an absolute fraction of the cost.