My opinion is that someone who is willing to migrate from their homeland to a strange country is:

1. in search of something better
2. takes great risk in order to find that something.
3. is willing to do whatever it takes to succeed unlike the 99% of their countrymen who stay put.

It takes a different type of person to do something like this. That's why I think they succeed much more than natural born citizens in the same line of work.