The argument continues to be advanced that the demands of spectrum efficiency require that spectrum be held by a small number of companies: i.e., AT&T and VZ. Magically, however, this does not reduce down to a "natural monopoly" that would require regulatory intervention to protect consumers and businesses using the wireless platform from abuse.
This most recently came to light with AT&T making a raft of acquisitions of licenses from companies not using them. While many are in bands already being developed, the 700 MHz band and the AWS band, some are in the WCS band, which AT&T needs to develop now that it has settled with XMSirius.
I call this the Hillel Problem, because AT&T basically argues "If not me then who?" But we must also ask: "If I am only for myself, then who am I?" In this case, the answer is: "A profit maximizing company with no competitive pressure to pass savings and efficiencies on to consumers and every incentive to exact monopoly rents from users of the platform."
Not sure tho what the right policy approach is. I am fond of reclaiming the licenses if the holders don't build out and making it available for unlicensed. But the expiration date on these licenses can be damn long. Still thinking . . . .