The companies in the middle east are always changing. Companies who are cheap and who do not rent expat compounds for teachers to live on and instead choose random hotels that are out in the boondocks generally penny pinch and do not share revenue equally. These types of companies also lose their respective contracts with the universities or schools rather quickly. Unfortunately the system of law over at the Middle East still has enough loopholes where if one company goes under for dishonest business practices there stands a good chance of another popping up. The company that I had signed up with in Saudi Arabia a few years back did not withhold your passport. But they were still crappy and treated teachers bad. But plenty of teachers did runners. With KSA if you do a runner in the city that you were working in there will be a 2 year blacklist (this was the rule a few years back don't know if it's changed now) imposed on you, but only in the city where you ran away from and not with the whole country. In some countries even if you have your passport you still need your employer's permission to leave. I believe you and some other teachers mentioned Oman as being like this?

As for the workers willing to put up with crap I think background factors in as well. Someone from Syria or Jordan will not experience as big of a culture shock if they just travel around the Middle East to work. They can even take a bus across the border to see their families if they live close enough. But the fact that there are hundreds of thousands of certified teachers willing to come and make some quick cash from the west means that while the number of people who go and teach may be big, they don't necessarily stay for long. Plenty will leave before their contracts are up.