[riemannzeta]

The question of whether specialization requires hierarchies is kind of the question that Coase sought to answer in the Nature of the Firm. To make a long story short, Coase thought the answer was "no" so long as it was more efficient for the specialists to contract with consumers of their services on a open market than it was for them to work together in a firm under managers. I think Coase's answer seems more obvious now thanks to the Internet. Back when he published it was pretty counterintuitive for a lot of people.

These days, I think hierarchy is required only where private information needs to be shared with the specialists in a carefully choreagraphed way. If we don't have to worry about who knows what when, then the specialists can synch up and deliver to customers just fine without managers. But if there's some super important private information that can only be shared in sequence with particular specialists in order to maximize a good result, then no hierarchy is a mess.

In other words, human hierarchy now is almost entirely derived from the architecture of private information.