I actually agree with the Chinese explanation. The demographics of expats v/s source country tends to be more even for developed countries because there is less need for their educated elite to migrate to the West. A gross disparity implies that the source country is experiencing a brain drain. Now, according to the stats, 70% of Indian-Americans have college degrees and, since 70% of Indians in India do not have college degrees, that should be cause for concern that the educated elite are voting with their feet.
Few things that I have always mentioned behind Indians migrating to US and other western countries for education.
First is that, Indian students either take educational loan or they may bear the cost. Also Indians and Chinese get Teaching Assistantship easily or being Research Assistant. reason behind is that the priority of Indian and Chinese students. For Asian students, the facilities which seems normal to local and western students, seems like high standard.
Another thing is Indians and Chinese are good in Mathematics, especially Chinese (look at their math Olympiad records) and Indians (if an engineering student in India scores less than 780 out of 800 in Quantitative section in GRE, he/she is considered dumb.) and Indians have edge over Chinese in English (which is diminishing)
That's why we see more Indian and Chinese students doing MS and PhD. One friend of mine just published a paper with a Chinese student under an American Professor. He says, Indians and Chinese go along well and work with ease.
Now these post graduates occupy the senior positions in the major companies. Many of them lead the R&D department. Masters and especially PhD gives initial boost to higher pay job.
Now the other western students like from US, Germany etc, they can go back and get similar pay job in their own country.
A research assistant in Spain earns 1,50,000 rps per month while same Indian learns hardly 15-25,000 Rps. Now think of the loan he has to pay and the money he can provide to his family and enjoy good life in foreign country. When he has enough money, he can lead a luxurious life in India.
As there is a German member here, their research institutes are world class.