2. The Indians in top leadership positions you see in tech firms are rare exceptions. To some extent they also come from fairly well off families and communities in India, who have social capital. Can afford cram school fees for Ivy league exams, money and ability to take loans to study abroad etc.
3. Any body who once makes non-trivial money or sees non-trivial career success instantly realises, given how big India is. Given its politics, and overall spending on Education, R&D, and the rate of industrialisation. The only hope for a good life for their, or atleast at their children is to move to the west.
Basically people want to leave India, as fixing India is largely a long term, and also a nearly impossible project.