This is not an easy subject deepu bhai. Here I live at the border state of Texas where there are lots of illegal immigrants from Mexico. Texans are different from rest of the America and they are largely sympathetic to the Mexicans. They say one thing. If there is a mother of some hungry children... and there is a job or food on the other side of the border; no government or law can prevent the mother to cross the border and get food for her hungry children.
This is a tangential way of saying that no government can prevent brain drain if there is a potential of such activity.
It’s natural for people to gyrate towards personal betterment and it is impossible to prevent it.
The solution is perhaps a better market economy. I have seen a lot of this brain drain. I am an example myself :)
When I left India it was before globalization and opportunities were few. But now I actually have friends who either stayed back in India or actually returned to India due to better opportunities. It’s a fact. And that’s the path forward.
RE: Responsibilities to the country