Ars Technica has an article on problems with WiMax and cellular wireless networks. As customers increase their use of high bandwidth services, the wireless networks can't keep up, and the result is that companies like Verizon and Clearwire have started reducing the amount of bandwidth they make available to subscribers. Clearwire's much ballyhooed WiMax network, just a few years old, is already congested and inadequate. And the much hyped 4G cellular data networks are not going to perform any better. The things that people want to do with their wired and unwired devices is accelerating faster than the ability of wireless networks to keep up. The problem with wireless networks is that you basically have to replace everything component in the network except the tower to add more bandwidth, so you are looking at something like 80% of the cost of the original investment to get an upgrade. With fiber, you can add bandwidth incrementally to individual customers who need it at very low cost, and if you did have to do a systemwide bandwidth upgrade for all customers (very unlikely), you would be looking at only about 20% of the original investment.
Wireless networks simply don't work without fiber. But fiber networks don't need wireless. It's simply physics, and marketing hype loses out to physics every time.