Remember too that many areas are too far out for even Wireless. And they are not that far from major civilization.
A good friend of mine lives in Tuscola Michigan. This very small town is about 5 miles East of Frankenmuth, MI. The only reliable means of communication he has is the POTS line. I have personally had Verizon, T-Mobile, Sprint, Nextel, and AT&T cell phones on his property. Of those the only one that ever got reliable communication was the Nextel. And that was only in his front yard. For some odd reason it wouldn't connect in his back yard.
Mind you, Frankenmuth, MI is not a huge city here, but it is certainly very well populated so it's not wasteland but it's not metropolis either. This falls true for many areas in Michigan I have been to.
And as for VoIP over satellite, good luck! Propagation delay on a satellite is upwards of a second for network communication. Anything real-time is unusable. This includes any games, etc. That's provided you have one of the newer systems that doesn't REQUIRE a POTS line for the uplink.
Note that anything over 100ms for delay renders the VoIP problematic, if not useless. I am a VoIP engineer for a living. We have to take all of this in to consideration before we even propose a solution to a customer.