Agreed, much like law enforcement did after prohibition ended, the crackdown on illicit cannabis production will increase and amazingly become more effective than it has been for the last 60 years.
Increasing Legal consumer access will go far too determining how long the black market can last.
Better quality, more variety, at reasonable prices, purchased conveniently, without the stigma of illegal transactions will go far too move “buyers” away from their long time dealers.
Without consumer access/ demand, the black market will have to find something new to do to make money.