Because no one in their right mind is going to buy those areas, not after FairPoint, Frontier, and Hawaii Telecom.
Another reason Verizon won't sell is because they figure they've found a way (Voice Link) to keep those customers without needing to really serve them. I mean, the companies I mentioned above were morons, but what if a competent company managed to get those areas and actually offer a competitive product? They might actually manage to hold those customers and dent Verizon's wireless strategy. No, better to use Voice Link as a way to hold onto those customers against the possibility that Verizon might find other products to foist on them later.