“In the late 1960s and early 1970s, the company was scaling back needed infrastructure investments in an attempt to maintain profits without raising telephone rates.”
AT&T went from 600 customers in 1877 to nearly 500 million calls a day in 1975. By the late 1970s it spent more than $10 billion a year on construction. Then it cut investment to protect profits, and customers waited for phone lines while service broke down. By 1977 it faced 50 antitrust investigations, and MCI got the Justice Department to break it up. A monopoly builds until building stops paying.