Personally, I think the #1 reason Marijuana truly hasn't been legalized yet is because it can't be patented. It has nothing to do with taxes or economy.
The problem is that they can't have ALL the profit, it would be a free for all.
And even if they wanted to patent a THC derivative or extract they wouldnt be able to patent every single strain. Theres just too many strains, anyone could cross a couple plants and have a new strain. Theres no control for One company to own the whole marijuana industry. Thats freedom, Thats democracy, and Thats scarey to the Government.