It's too early to tell. They only just started issuing retail licenses this past month. It's slow going because each store has to meet stringent standards. But

It's too early to tell. They only just started issuing retail licenses this past month. It's slow going because each store has to meet stringent standards. But they're opening one by one. The taxes are applied at a rate of 25% at each level of the system: growers, processors, and retailers. The remainder are standard business taxes (B&O tax) and sales tax. From what I've seen, everyone involved has been very conscientious in implementing this law and have made adjustments to ensure that it works. If the black market continues to thrive due to taxation that is too burdensome, I expect they will adjust accordingly.