> What would be the drawback of simply creating a global fund for actual human cleanup at scale? With some set incentivizing price for retrieval, say $0.01 per gram?

I'm imagining huge machines trawling the landscape, chewing up beaches and scouring forest floors, controlled by bots that automatically guide them to the nearest plastic recycling depot where they disgorge their contents and then move on. They'll be powered by burning plastic and will thus be self-sufficient, albeit enveloped in toxic clouds of pollution. Occasionally one will lose Internet connectivity and rampage through a small village in the developing country in which it operates (deployment in Western countries will be prohibited), obliterating shanties and the occasional elderly person, baby, or otherwise slow-moving human being.