It seems to adapt to life abroad is too hard for many teachers. Having a boss that speaks another language, looks different.
This has a lot to do with many Westerners raised to see other non Westerners races inferior (no pun intended to all Westerners). Granted, many school bosses are crooks and take advantage of the teachers. Also, many under developed countries in Asia do not have or enforce laws to protect the teachers contracts and fair paid salaries. Being a foreigner in any country is not easy, it not matter how hard you try to assimilate into your host culture, you will forever be an "other".