When millions of U.S. soldiers returned home from World War II , they faced a severe housing shortage. With few new homes built since the Great Depression , G.I.s and their young families were forced to live in garages, tool sheds and even converted trolley cars. At the time, the average homebuilder in America constructed just one new house each year, but the United States needed an estimated 6 million new homes to meet the demand. Starting in the late 1940s, a handful of ambitious U.S. homebuilders addressed the postwar housing shortage by mass producing nearly identical cookie-cutter homes in large suburban developments. Henry Ford had shown that unskilled workers could manufacture high-quality, affordable products if every step of the process was simplified and repeated. These companies applied Ford’s assembly-line economics to building houses. In the 30-year period following WWII, more than 40 million new housing units were built in the U.S., according to a 2011 California state report.…