You are probably right that there is nothing that can be done to clean the plastic pollution from the oceans. Yet, if there were several of those floating booms in the more polluted areas and thousands of tons of plastic were recycled each year at a profit then my vision of unicorns and butterfly sneezes would move from fantasy to reality. Plus it is fun to hope that technology and capitalism could solve a problem. As long as it is not my money, then let them give it a try.
Good points all.