I don't know. Analogously there was a long period when IE dominated, and you could make a case that the web browser was a natural monopoly, and trying to compet

I don't know. Analogously there was a long period when IE dominated, and you could make a case that the web browser was a natural monopoly, and trying to compete would at best just end up in a different monopoly. I'm glad someone went ahead and challenged it anyway. An oligopoly is better for us than a monopoly; a two-party state is much better than a one-party state; and with a mechanism in place for competition, a monopolist must act more like a competitive firm even when the competition remains only potential.