Okinawa was placed under U.S. rule for 27 years after the end of World War II. During this time, the Japanese mainland succeeded in rebuilding its economy, in particular securing high economic growth through the development of heavy industries, and thus joined the ranks of industrialized countries.
However, during this time, Okinawa's economy remained dependent on demand generated by the U.S. military facilities, and the prefecture developed a unique economic structure that lacked the engine of growth we call industrial production.
True, the U.S. bases provided income, but this was not accompanied by an accumulation of capital, nor by any production. In other words, Okinawa had within it an area to which its inhabitants could turn to for work.