You definitely have some great ideas about hemp, hemp plastic and how to clean up the oceans. It has been estimated that 70% of the plastic sinks to the bottom of the ocean, so we’re going to need to do more than just scrape it off the top.
As to whether or not capitalism is the answer, I’m not so sure. It was capitalists who influenced the government to ban hemp. They will surely use their influence again if and when they see a need to do so. If capitalism is the solution, then capitalists must be willing to remove the influence of money on government.