I can speak for Argentina in this case: first and foremost, an average entry-level programmer in argentina might make 600 dollars a month. There is no consideration for your degree in that regard.

Second but not least, because ARgentina grows so much on outsourcing contracts, the quality of the job to do is poor and uncommitted. Product management in Argentina is almost non-existent. This means that the most likely job you will get is contracting-"do as the guy that pay exactly wants even if you know for a fact that there are better ways to do it" work.

So, more pay + more interesting work is enticing enough. Also, having worked in the US gives you a halo if you come back.