Because it's wishful thinking along the lines of 'oh, great, internet out of my tap, why didn't I think of that'. This is a problem with many technologies that would be great to have but that are a lot harder than they seem to be at first glance, for instance VAWTs have been soaking up funding for many decades now and will continue to do so without ever giving a proper ROI because it seems to be such a great idea that every couple of years it goes through a revival.