Follow the seniors, is what I can say for the payback issue. Of course, someone could give more than them, if they wish.
In every field what Indians needs from IITens are:
1. The Expertise i.e. "IIT = HBS + MIT + Princeton" 2. The Funds to develop Industry and Finance to develop Research facilities.
There are more such issues, which need wider discussion scope and platform.
Still, Congratulations to the batch of 1980s- IIT-Bombay. They have taken initiative and many such will be followed by the next batches.
Similarly, IIM, NIT, other MBA institutes must help the local schools and the colleges they learnt. So that the real Guru-Dakshina is worth enough to be remembered by all and must be followed by all, successive generations.
We did it with our school, college and city of birth and the institution we worked and the nation we worked. Though, we are not IITen still we did it for our institutes and organizations we were associated with, as much as we could.
Hope our next generations will follow the seniors, as we did.