Maybe. But I think the majority of people would rather purchase legal products, even at higher prices. I know a fair number of cigarette smokers, and even though cigarettes are astronomically expensive due to taxes, I have yet to meet someone who seeks out smuggled cigarettes to avoid paying the taxes. In general, I think people prefer to be on the up and up, if they can do so without too much difficulty or pain.
Secondarily, getting something illegally is usually a hassle. Sometimes a minor hassle, sometimes a pain in the butt. Plus the risks involved. People will certainly go to the trouble and take the risks if the choice is to do so or not to have what they want at all. But if they can get what they want without the effort and risk, they will likely choose the path of least resistance, even if it costs more.
This will be evened out a lot when the Federal government finally gets its head out of its *** and legalizes marijuana everywhere, or at least at the Federal level and leaves the States to their own devices.