They have freedom inherent in our system that they do not have in their home countries. Anyone who wants to work hard in America can make it.
Freedom, motivation and -- as cornball as it sounds -- a belief in the "American Dream." In New York you hear these stories all the time. One guy I know swam -- swam! -- out of Albania on a bunch of inner tubes. Another guy I know fixed cars in "Trench Town" Jamaica to come here. Both are either millionaires or close to it.