Also, I think in at least some cases, the initial knee-jerk reaction of 'why are they doing rural areas/smaller towns' is often incorrect if you don't actually take the time to do a little research and look up where some of these places actually are located as well. I posted this in another thread, but just for example in Tennessee, these assumed rural areas/smaller towns that were listed on the 100 'coming months' press release are actually right along the path or within range of an interstate corridor, which to my mind makes total sense, because I think in general, people expect or at least are under a fair impression that they'll have good service when they travel by vehicle along an interstate.
In fact, in my own case, its because of that reason that I switched to Sprint from AT&T in the first place. I-40, which just-shy-of-literally spans coast to coast, passes right through Cookeville where I live, and until roughly March/April of last year, AT&T still didn't even have 3G implemented here.