Is this fundamental attribution error? Perhaps the reason it is more expensive is because it presents much less of a risk to purchase vs. on the street? It could also be that there is not a lot of competition selling legal weed. Maybe it is because street prices have dropped considerably due to the introduction of legal weed?

Furthermore, it should be noted that Colorado's laws also permit growing and gifting marijuana legally. Why buy it when you can grow it yourself or get it for free from someone who grows it? Sure you can only gift/receive/travel with up to 1 ounce legally and one could also make 16 separate visits (pun intended) to a friends house as well.

Perhaps any or all of these are factors in the price or maybe it is overtaxed to the point that people are still willing to obtain theirs the old-fashioned way.