 Why did AT&T originally retain ownership of the phones at the endpoints?
The solution to this increased complexity in the late 19th, early 20th century was to increase the role of structure and improve its design. But the impulse to build fully-specified systems, designed by experts, monitored and controlled so as to limit human greed and error and to manage uncertainty, was basic and widespread. It underlay the development of the enormously successful state bureaucracies that responded to the Great Depression with the New Deal. For a moment in history, these large scale managed systems were achieving efficiencies that seemed to overwhelm competing models: from the Tennessee Valley Authority to Sputnik, from Watson’s IBM to General Motors.
 To ensure the proper functioning of the networking and monitoring of customer behavior.
 To prohibit customers from connecting unlicensed phones at the endpoints.  To exclude competitors.  To ensure the proper functioning of the networking and monitoring of customer behavior.  To make the most profit.