http://collectiveidea.com/blog/archives/2016/01/15/wisp-tria...
Basically, if you think that in developed areas cell tower density has or should have an inverse correlation with the cost of bandwidth, then you don't live in the real world. There's a reason that there are only a few network operators on most towers, and those guys get away with highway robbery in terms of pricing and quotas.
Here is the money graf:
"It’s when I began seriously working on the cell tower option that the beauty and inevitability of the balloon idea truly clicked for me. Don’t get me wrong — on its face the Internet balloon idea is still actually nuts, but it’s vastly better than the terrestrial alternatives, which are all terrible because of one fatal problem: any moderately long-range wireless bandwidth solution needs line-of-sight to work, which means you need elevation, and (absent a viable balloon technology) elevation is a function of geography, which makes it eminently exploitable by rent-seekers.
This geography-based rent-seeking, by both wireless carriers (via national tower networks) and fixed-line ISPs (via cable, fiber, phone networks, and trunk locations) is the only reason that bandwidth quotas exist in 2016, and it’s what brings the Internet-of-balloons idea down from cloud cuckooland and into the realm of inevitability."