India gets a metric fuckload of money back in remittances every year. Debatable if that's actually worth the brain drain, but then there's also the angle of having your young people learn from the rest of the world and return with new skills. I lean more towards the remittances though.
I have seen a lot of smart people in thrall of ideologies that could be used to manipulate them left and right at will. Meanwhile, true morons tend to be unpredictably chaotic.