Situations similar to Wang Lung’s have, in fact, occurred in the past, and some are happening even now. Some examples include the Communisation of Russia, the Great Depression, and the Industrial Revolution.
The Communisation of Russia is perhaps the most similar to what happened in China at the time of The Good Earth. As Vladimir Lenin brought the Socialist party to power, people began to desert their rural roots and move into cities. Many people signed up for industrial and scholarly jobs. Young men joined the military in a wave of patriotism that turned Russia from a faltering behemoth into a prosperous world power. Similar anti-capitalist agendas were pushed in both countries at the time of their revolutions.
Another similar situation is the Industrial Revolution. As factories and plants for mass production and processing sprang up, many left the homestead in search of opportunity. These farmers flocked to cities, where they would work in grueling conditions for what we would consider to be little pay. They also went to work on things like railroads, modernizing America through labor. The exodus to cities was so massive, that between 1800 and 2000, the population living in or near cities went from 3% to a staggering