David I. Rosenbaum
The conclusion begins with a review of how firms in these ten industries gained dominance. A number of commonalties arise across the studies. All but one of the firms rose to dominance either as a first mover or early in the industry's life. Several were propelled by the vision of a key individual. Most developed cost advantages over their rivals. Typically this was done through research and development, learning-by-doing and economies of scale. Most worked to stimulate demand by process and product development, differentiation, and advertising, and through the use of specialized sales forces. In a number of industries, large market shares created externalities that supported further growth toward dominance. Many maintained low prices. However, episodes of focused predation and other anticompetitive behaviors were not uncommon.
The focus then turns to the maintenance of dominance. Dominance was maintained when firms were able to maintain advantages over their rivals. The sources of the advantages varied. Some were derived through efficiency-based actions such as cost advantages or investments in creating better technologies. In a number of these industries, however, an advantage was fostered through vertical integration or tying. Integration and tying slowed the development of secondary markets and retarded entry into primary markets. In this sense, they prevented competition when it may have developed if either integration or tying were absent. Vertical and horizontal integration also supported limit pricing, price discrimination, episodes of limited predation, and key acquisitions that thwarted a concerted effort to enter. The economic efficiency of many of these actions is