The desire to tax and to regulate is what killed the hemp industry. The Marijuana Tax Act of 1937 imposed taxes and regulations that made hemp economically unviable.
I expect the timber industries lobbied hard against hemp as well (companies like DuPont.)
Ironically, William Randolph Hearst published 28 newspapers across the country and a dozen magazines. He lobbied with his press assets against hemp. Interesting because you’d think that a newspaper publisher would want to use hemp to reduce costs. Hemp would be cheaper to use had the tax bill of 1937 not been passed.
Hearst’s mistress, Marion Davies had a serious appreciation of pot and Old Man Hearst was SERIOUSLY ANTI WEED , so that explains a lot.
If he knew he could’ve grown it anywhere, he had half the midwest back then! Jack Ass! Also, if the English had discovered weed long before coming to the New World, we would be a chiller planet. Just a theory.
Hearst knew alright but he was a mot*her/fooker who did not like anyone have a good time.
The British Crown grew Hemp to make rope for their Navies enormous demand for rigging and hanging .
It grows naturally all over this planet even in Siberia and in my greenhouse. 
Hemp has been cultivated and used in the UK for centuries for its biomaterial properties – in fact its long fibres have been spun and woven to make sails, rigging and ropes for ships since before the Elizabethan era. Now it is making a comeback for very different reasons. 