I think widespread 3G is making the range less of an issue now. I can see providers - third party or not - using existing cellular networks offering data-only plans that make this far more feasible.
From the phone company's view there are only data networks, voice networks are dying out. Voice is just another form of data.
Instead, Verizon for example, likes to charge per minute, text message, and media message if you are not on an "unlimited" (which is actually limited unless you are truly grandfathered in from an unlimited plan)
I think a lot of people would welcome a 'data plan bill' only and get rid of the nickel and diming