If you look here: http://wireless.fcc.gov/auctions/default.htm?job=auctions_al...
You can see the amount of money that goes into the auctioning of the bandwidth. You have to pay in the millions of dollars before you can build a single tower.
It is a capital intensive business, and I don't suggest otherwise, but it seems to me that there is absolutely no incentive for any of the major players to innovate, as the market is locked down as soon as a chunk of bandwidth has been bought.
It would be nice if there were another way of structuring it to encourage competition in this particular market. One possibility might be to have a local distributor, and then competing vendors that work through that distributor. That is just of the top of my head, so I'm sure there are problems with it (I can certainly think of a few).
It's also unclear to me how much this has to do with "monopoly power" and how much it is simply the case that mass Internet access is an extremely capital intensive business that will always be led by large companies.