Many have returned back home, or got to that level locally and don't want to leave.

The Indians I've worked with who returned say they did it because life was easier. Sure they make less money on India, but in India servants come every day to cook and clean (for about 60 cents a day). As one guy said "I know how to cook, but I didn't realize I'd be cooking every meal"

not true. it's a huge country and there are so many reasons why people decide not to emigrate particularly with the visa hassles worldwide and evolving startup scene in India.