As freight transportation became more reliable and less burdensome while tariffs on imports faded away, differences in production costs came to dominate companies’ decisions about where to make their goods. Two factors in particular loomed large by the final years of the twentieth century. One was wages: the gap between the pay of factory workers in China, Mexico, or Turkey and those in Europe, Japan, or North America yawned so wide that even if the low-wage workers accomplished far less in an hour of work, producing abroad rather than at home made financial sense. The other draw was economies of scale. Where an automaker’s parts division would likely make headlights only for the parent company’s cars, a headlight specialist could sell to many automakers, producing at enormous volume and, by spreading its administrative and engineering costs more widely, lowering the cost of making each unit.