A few unlicensed wireless systems exist, namely, Ubiquti's AirMax (http://www.ubnt.com/) and Cambium's ePMP (http://http://www.cambiumnetworks.com/). The problem is that these systems are often set up by people with no knowledge of how radio or the Internet works. Imagine a residential DSL connection being resold to fifty people while being made even worse by radio interference and propagation issues. It is possible to build an ISP while bypassing a local monopoly, but few have the requisite knowledge.