There is nothing natural about a monopoly (or in this case, oligopoly) ordained by government. And that is the problem that should be addressed directly. Current government policies create an absurd amount of artificial spectrum scarcity.
Edit: Obviously I wasn't clear here -- I should have been straightforward rather than going with a clever turn of phrase. I meant to say, as a point of accepted definition, that government-granted monopolies are not 'natural monopolies.' Natural monopolies are monopolies that occur 'naturally' in the market because of conditions or extreme capital requirements.