It stands to reason that the government would want it to stay illegal. If it becomes legal at the federal level, think of the implications. The govt knew about remedies this plant possesses and yet kept it from people. Lawsuits would follow. Unless there is perhaps a provision for them not to be. Aside from that, Cannabis legalization would thoroughly turn the economy upside down from what it is now..in my opinion. The paper industry would be effected along with the oil and gas industries. Govt don't want this as they would lose their fat paychecks.
for me, the real solution is complete decriminalization, not legalization.
The data online would suggest that it was the paper industry that originally campaigned to include hemp (the non-hallucinogenic strain of cannabis) in the drug laws, and mounted a propaganda campaign to support their effort. Until then, hemp was a major economic product, in fact Henry Ford built a prototype of an automobile from hemp plastic that outperformed his metal skinned autos many times over. -It became moot, when the source commodity for the amazing vehicle was made illegal, soon after. I begin to despair of a population the has so much information at its fingertips, yet still allows a greedy few to dictate our limits, our lifestyles, and our quality of life itself.