There's nothing obvious about floating communication networks. It takes a pretty large amount of engineering to get right. There's a massive difference between satellite vs balloon based communication that I don't know why the comparison even needs to be made. To totally reduce the two to "falling towards Earth at a different altitude" (which isn't even accurate for balloons) totally ignores just about everything that makes them different. It's like saying the idea of a car can't be patented because it's just a hunk of metal on wheels and we already have bikes that fit that description.