Pacific Gas and Electric makes a healthy sum off of my family, even though the candle-makers of 1815 would see it as the next thing to giving away energy for free. But we consume a lot of energy. After the heroic age, firms make money by giving customers exactly what they want. But after the 1920s, Ford got overwhelmed by Alfred P. Sloan's General Motors, which figured out how to retain most of Ford's economies of scale while at the same time proliferating brands, models, styles, and colors to get close to individual consumer demand. Before GM, no one knew what kind of options car buyers really wanted.
Some firms wind up larger than anyone had every imagined.
Everytime a leading sector goes through a heroic entrepreneurial and technological burst, it changes the opportunities to realize economies of scale. Each burst leaves us with previously unimagined capabilities. The railroad gave us the ability to cross the continent in a week rather than in months. Electric power gave us the ability to light our houses. Metallurgy gave us the ability to build some really big buildings and bridges.