Here in Arizona, it drove prices so low it isn't worth the risk of a black market. Dealing in cannabis in any form with the proper license and permits is still a felony here. In fact, in my county, the bootleg growers are given to the feds for prosecution under federal law.
The prices dropped so low that I don't grow any for sale any longer, just personal use. For the past four years I have supplied 4 people, now 3. (One died). No, I don't charge them. I get enough yield for all of us from the plants I am legally allowed to grow for myself.
I used to grow for a couple dispensaries. When Arizona started the medical marijuana program, I operated a dispensary. After the 3 years I was required to keep it in the location the state mandated, I closed down and sold the dispensary license and the new owner moved it to Scottsdale. I continued to grow commercially for 3 more years. Then the price fell so low it isn't worth my time.
Still, in Arizona it is not worth the risk to engage in black market activities. It may be different in other states. I know of a few p that used to operate legally that now transport their harvests to states where there is no legal market. That doesn't sound like it's worth the risk to me either. But apparently some folks think it is because they are doing it .
I also know of one person who switched to growing poppies, and selling the opium. I am not interested in that activity either.