Marty Cooper is right: If we are efficient, "There is no spectrum shortage and there never will be." Showing there's enough spectrum if used efficiently, Marcelo Claure concludes "[Our] spectrum holdings are sufficient to provide its current and future customers." Claure has ~100 MHz in high frequencies, so much he is thinking of using some of it for backhaul. (The FCC should stop that, and other many wasteful practices, in the name of efficiency. But true efficiency is generally ignored.)
Cooper, the inventor of the cell phone, was joined by Marconi Fellows A.J. Paulraj, John Cioffi and Vint Cerf in projecting technical advances that could raise wireless capacity 50-100 times. The engineers convinced me until the companies spent $45B in the last auction. That's 3-4 times as much as the experts I respect predicted. I don't think anyone well informed is certain of next year's results.