contracts -- are in the best financial position to build out their 4G networks. Having those networks, in turn, makes the largest carriers even more likely to attract even more customers. And this is the economic dynamic that could turn the U.S. wireless market into a Verizon/AT & T duopoly, with only some discount carriers surviving on the fringes. For U.S. mobile users, further wireless market consolidation is a good news/bad news situation. It offers the promise of ubiquitous high-speed wireless broadband networks available in markets outside major metro areas, which would lessen the geographic aspect of the mobile digital divide. But just because wireless broadband is available in a region does n't mean everyone there can afford to use it. A less competitive wireless market could mean wireless broadband wo n't get much cheaper. And it could even get more costly, especially if tiered data plans become the norm -- which would make more sense for the carriers in a less competitive environment. That would be bad news on the income/class front of the mobile digital divide. Lately, T-Mobile has been taking a bit of a beating in the U.S. market. Bloomberg noted: T-Mobile... has lost customers at an accelerated rate as it trailed rivals in building out a third-generation mobile network and missed out on being able to sell Apple's iPhone. About 56,000 customers abandoned T-Mobile