Marijuana is the largest cash crop in the U.S., with hundreds of millions of dollars being lost as potential tax revenue that our states coffers dearly need.
I've wondered about that as well. Marijuana does have medical benefits. One of my Aunts had trouble holding her food, after just a couple of hits she was able to eat an entire meal after days of not being able to. the reason Marijuana is still illegal in the US is because it is a mind altering drug. despite that many OTC drugs can give you the same effects like driving while you're sleeping, it is still illegal. I have never heard of anyone overdosing on marijuana before.
I don't smoke it myself but I think if marijuana was to legalized there would be similar laws people would have to follow, similar to the drinking and driving laws.