Even with the passage of so many new marijuana laws, the Feds - and, by extension, the states - are stepping on eggshells. They still have the Reefer Madness mentality.
As an example, here in PA ... yes, they passed the medical marijuana act, and it will theoretically be implemented in a few years.
Problems:
Supply
There are only 4 grow facilities currently coming online in the several surrounding counties. In news interviews with the locals, the majority of them had a "not in my backyard" mentality. It's going to take time to educate these people, if that is indeed possible.
Getting It
Old-school doctors here were brought through med school being taught that weed is a killer drug. They aren't likely to change their minds now. The younger docs, although more open-minded, are often constrained by the leaders of their medical groups. "No, we don't want anyone having anything to do with this!"
Another point is that the docs cannot prescribe medical marijuana: they can only recommend it. This will be another great hurdle to clear.
Public Perception
Once again, this area has an older population. The youngsters flee town as soon as they can. It's an overwhelmingly anti-marijuana atmosphere here. Education will take quite a while.
DUI Laws
Our present DUI laws are not set up with marijuana in mind. There is no valid test for impairment with weed. It stays in the body for about a month, far longer than most other drugs or alcohol.
Law Enforcement
As with the doctors, the LE community has been trained to see marijuana as the Enemy. This will take time to overcome.