Brain drain is good for India, many American scholars claim, since these IIT graduates learn new skills and will help India rebuild when they go back after a few years. Meanwhile billions of dollars sent asremittances sent helps India. Moreover, many IIT-trained Indians in the USA, who have achieved business success, are determined to help India open more technical and management schools so that more Indians can come to the USA and achieve success as they did.
Indian parliament cares about it since IITs are the pride of India. We are told that yes, some of the IITians are leaving India but still about two-third of them remain in India to serve India. Problem is that out of top quarter of IIT graduates, in fields like computer science and electrical engineering, most leave India. While IITians are of high quality, not all IITian are created equally and the impact of losing those IITians is perhaps more than one third.
A few good ones who don't go abroad, are selected by multinational like Hindustan Lever to sell consumer products like soap. A few others go to management schools and work mostly for multinationals like banks. Of those who are of technical bent (isn't IIT technical), many are absorbed by the IT industry with companies like Infosys which basically supply cheap off-shore labor to foreign countries. Few are left to work for other industries in India.
No. Most of them are not going to come back. They will talk about it but as they get married and have children and become settled in their careers, it becomes more and more unlikely. Some of the immigrants from countries like Taiwan and Singapore went once the income difference between the two countries narrowed. Not likely to happen soon in case of India. Politicians talk about making India developed by 2020, which is not realistic. IITians, in the rare cases where thy go back to India, will most likely work for some non-Indian firm.
In nominal terms, yes. The supersmart students of IITs - the ones who leave for USA are worth much more than that. A country disproportionately depends upon its 'brains' and IITians are worth much more than the nominal cost of educating them.