Think of the itinerant worker in the US in the 1920s and 30s, and even into the 50s. Many workers from the South, for example, traveled north for factory jobs, worked for a while, then went back home. My wife, a sociologist, studied the Birmingham AL-Detroit migration route, which often took two days (and, sadly, still does on public transportation). The housing situation was cramped and miserable. My grandfather once told me he lost a third of his workforce after Thanksgiving, and gained it back after Easter. He did not offer great paying jobs--but they were jobs. From what I've seen over the past 30 years, China is experiencing those same fluctuations/migrations, but with 7X the population (of the 1950s US).
