In our family we had always known that my engineer grandfather had emigrated to the USA before WW1 - to the Detroit area, we think - where the newly developing automobile industry had employment opportunities. Why America? Emigration to the USA was unusual for people from here - Britain and Europe was the natural region.
As a family we had no opportunity to discuss why he went, what he did there, and most importantly, perhaps, why he felt he had to return after 8 years. Was he following an American dream, and why did it turn sour - sour enough to never mention the experience? In those days, crossing the "Black Water" was social and religious taboo for the orthodox here - after return to his provincial village, he had to spend 2 weeks living out side the main house and prayers had to be offered as "expiation" for the sin of leaving the sacred soil of the country. How bizarre these rituals must have seemed to him, after 8 years in the land of the free! The only memory of his stay in the USA is his old Keuffel and Esser slide rule stamped "1908" (which I still haven't worked out how to use).
In the past 25 years, several of the family (and extended family) emigrated to the USA. Why now, in spite of better opportunities that have developed here in the past decades? They followed a trend. Perhaps they are better at grabbing available opportunities, opportunities that were not available pre WW1. It is interesting in itself that such opportunities are available at all, in that native Americans obviously do not think that they are worthwhile enough to take up in numbers - in spite of the opportunities being highly-paying.
According to the 2000 U.S. census, the overall growth rate for Indians from 1990 to 2000 was 105.87 percent. The average growth rate for the whole of USA was only 7.6 percent. --- According to the 2010 U.S. Census, Indian Americans had the highest household income of all ethnic groups in the United States. According to the American Association of Physicians of Indian Origin, there are close to 35,000 Indian American doctors. Among Indian Americans, 72.3% participate in the U.S. work force, of which 57.7% are employed in managerial and professional specialties. In 2002, there were over 223,000 Asian Indian-owned firms in the U.S., employing more than 610,000 workers, and generating more than $88 billion in revenue.[25
The "acceptable immigrant" has always been an interesting phenomenon. Hobbesist pointed me to Albion's Seed, indeed a fascinating read all round, since I worked for many years in those parts of England where the four designated cultures arose. I'm interested in getting more perspectives, and have ordered "Ethnic America" by Thomas Sowell and Different Mirror by Ronald Takaki. Any other suggestions?