While onerous regulation is probably a significant contributor, the continued existence of California's black market is probably helped by the fact that a lot (

While onerous regulation is probably a significant contributor, the continued existence of California's black market is probably helped by the fact that a lot (by some estimates ~60%) of the cannabis in the country was coming from California pre-legalization, the vast majority from a couple counties on the rather remote northern coast. The culture there is the intersection of hippies and libertarians (of both the left and right varieties), a conglomeration basically joined exclusively by their general disdain towards government oversight. A lot of farms went legit, but it's not exactly surprising that others didn't.