Final answer:
The transition from wartime to peacetime economy, characterized by businesses shifting to domestic production and the end of wartime controls, directly contributed to the economic changes between 1919 and 1921. This led to inflation, worker strikes, and the emerging U.S. economic power. Underlying weaknesses, however, foreshadowed the upcoming Great Depression.
Step-by-step explanation:
The economic changes that occurred between 1919 and 1921 can be most directly attributed to the transition from a wartime to a peacetime economy. This period was marked by the recalibration of businesses shifting from war production to peacetime goods, such as toasters and cars. As wartime controls ended, this shift resulted in inflation as public demand outpaced production, leading to shortages of consumer goods and nearly doubling the cost of living from 1916 to the end of 1919. This economic upheaval was further compounded by workers striking for better wages and hours, responding to their diminished purchasing power and the end of no-strike pledges made during the war.
Additionally, the postwar period saw the United States emerge as an economic power, extending credit to other nations and witnessing a rise in consumerism fueled by technological innovations and the availability of credit lines for purchase of new appliances. However, the prosperity of the late 1920s concealed underlying economic weaknesses that ultimately contributed to the Great Depression. The predictive warnings of figures such as John Maynard Keynes about reparations and their burden on Germany also hinted at future economic turmoil that could affect the broader European economy.