Well the one thing you are right about is the governments being different.

Cell networks are modular as such those can be compared per capita, not per absolute. USA has population density twice of Finlands. Also since these are cell networks affordability can be talked network wide instead of locally. Sure that one Winston farm is not affordable, but we'll the local city already makes up for it.

Upon which we come to the reason we can demand they take that hit of providing for Winston Farm and not just picking the cream from the top by sticking to the city.

Common good or public good. Limited shared reasource, that can't be utilised without affecting others. If one company gets for radio band and is choosing to not provide for Winston Farm, that shuts out company B. Company B was also going to utilise the radio band, but their plan was to serve Winstons also. Company A thus excludes ability of winstons to be served, even if winstons wanted to be served and willing to pay fair price

Same as we don't allow companies to pollute air endlessly, since it denies the ability to habitate in the polluted air. There is only one atmosphere, there is only one radio space around Earth. It is only feasible to run one water network, one electricity grid in a city. In that case the shared common good is just the space itself. If someone puts up an utility pole on the only strip of land next to the road, someone else can't.

There is more than one radio band, but only limited amount.