James M. McPherson writes,

This pre-industrial world could not survive the transportation revolution, which made possible a division of labor and specialization of production for ever larger and more distant markets.

The transportation revolution includes canals, steamboats, and railroads. It took place roughly from 1815 through 1855. Before this revolution,

Americans produced on their farms or in their homes most of the things they consumed, used, or wore. Most clothing was sewn by mothers and daughters, made from cloth that in many cases they had spun and woven themselves by the light of candles they had dipped or by natural light coming through windows in houses built of local materials from a nearby sawmill or brickyard by local carpenters or masons or by the male members of the household…[few]items were sold more than twenty miles from where they were made

Before the transportation revolution, McPherson writes, the price difference between wholesale pork in Cincinnati and New York was $9.53 a barrel. Afterward, the difference was $1.18 a barrel. The railroad cut the travel time between New York to Chicago from three weeks to two days. Before the transportation revolution, it was cheaper to transport goods from the East Coast to Europe than to transport them thirty miles inland.

Today, we take specialization and trade for granted. We get ticked off when the government “fails to create jobs.” Yet the unemployed do not revert to growing their own food, sewing their own clothes, and dipping their old candles.