It is nuts that this sort of problem exists in the first place. IMO this nonsense about company A not having reception in Town B and company B not having reception in town A is a glaring example of one of the basic flaws of capitalism, namely a tendency to unnecessary duplication. It's one thing when a society's resources are used to produce a hundred different floor cleaners all doing exactly the same thing, but when it comes to something that is rapidly becoming a near-essential, like the mobile phone network, it's quite another.
Many people who are hardly dyed-in-the-wool Marxists are fiercely critical of Rail privatisation as a service that is not best served by a naked free-market approach, yet even there nobody would suggest that each Train Operating Company build there own rail network connecting the same cities.
In these days of uber neo-liberal orthodoxy, I fully expect to get flamed to death, but in my idea of a sane world the mobile network would be a public one, or at least a national private one like BT's, with companies providing the services all using the same network and competing on price as well as other benefits and services and not simply reception. (And on that note imagine if the landline industry had always been privately owned and had evolved in the same way as the mobile industry, with each operator having it's own individual cabling which duplicated that of its rivals).
That would at least produce a more sensible market for those who get off on that sort of thing - consumers wouldn't be forced to stick with a company they hated simply because nobody else could give them a signal in the Back of Beyond.