Ask HN: What happens to the "drinking water" devices that pop up daily on HN

It seems that (to exaggerate a bit) everyday there's a revolutionary invention of a cheap portable device that uses very little energy and generates enough drinking water for a family. What actually happens to those devices? Surely there's money to be made there? How do I not see a production version.

I guess my bigger question is, what are the logistics and economics of bringing unprofitable inventions that target poor people.