Typically the 'lure' is to escape to a progressive society. It may pain you to hear it, but most countries that have higher education have a more educated populace. A more educated population tends to not be stuck in the social and religious moores of the past. Some countries (typically Islamic based Governments) have an education system in place that is trying to control education, so as to NOT allow a full and complete school system to teach all. (The Male dominated Society comes to mind here) Some countries have a political or Caste based education sytem. (China, India) Only some of the citizens are allowed to attend school. Some are relegated to be the low class, and to serve the upper class. In addition to the society, the money certainly helps.
It is common knowledge that money is a necessity and the more you have, the better you can live. Young people are ambitious and the higher packages offered by western countries are simply irresistible. They are a means to achieve their dreams.
Jobs in American are very scarce....not many. 20 something million people have no job or are working part-time, no benefits. Outlook is not good for another 5 yrs or so, or until Democrats realize that America is really hurting. People go where the jobs are. Half of the unemployed now are on food stamps and drawing unemployment money. So, with no jobs here, you must look elsewhere. By the way, over half of college graduates in 2010, 2011, 2012, can still not find a job.