It is usually a mistake to suppose that a company is the best judge of how its business works. Or that an industry is the best judge of how the industry works. AT&T is a good example. When the Justice Department sat down with management in 1981 to negotiate a breakup of what was then a monopoly provider of telephone service, government lawyers asked which part of the company management wanted to keep after the breakup – the long-distance operations or the regional networks. The long-distance operations had long been the company’s most profitable, so management asked for those.