http://en.wikipedia.org/wiki/Resource_curse

If you were a mining engineer, would you want to travel to Afghanistan and spend a year or two setting up a new mine there?

Do they? The Saudi Arabian ruling classes do very well indeed, but how does the average Saudi do? Hint: google "Saudi Arabia inequality" and "Saudi Arabia oppression". It's the resource curse at work.

That's the official line, anyway. The whole issue of who is a citizen, and who has merely been there for years is part of it.

They were desperately poor before they went to Saudi Arabia, the Saudis merely gave them a marginally better option.

the Saudis gave them what looked like a marginally better option.

It's not a difficult issue at all, you're a citizen if the law says so. No one promised guest workers citizenship and I doubt they expected it. Only westerners subscribe to the novel idea that anyone they let into their countries are also owed a part of it (citizenship, welfare etc.).

"the Saudis gave them what looked like a marginally better option."

There are five million guest workers, a lack of horror stories would be surprising. I'm not convinced coercion to stay is widespread before I see some statistics, if coercion to stay is not widespread then I trust that most of the five million guest workers know what is best for them.

Not necessarily. The U.S. economy was built on drugs when it was starting out. Even today most of our famous colleges are named after drug families.

Which famous colleges do you have in mind here?