At the start, agriculture had made New England families self-sufficient. In the 1800s, it became a profit-making enterprise, especially as the railroad opened markets farther from home. But over the course of the 19th century and into the 20th, farming also became a race to offset narrowing profit margins by expanding sales and creating economies. A major part of the problem was the so-called "tragedy of the commons:" what made sense for a single commercial farmer — producing more goods for sale — was not in either his or the common interest when everyone did the same. More production meant more supply for a limited market. More supply from local farms and still more from beyond the region depressed prices. Profitability suffered.