The answer is Family.
My parents had never wanted to settle there. After I and my sister were born, we sort of settled, but the plan was to go back at one point -- I had grandparents in India. So we did. I found it hard to adjust, but I managed. (We used to visit every year, so that helped).
Regarding education: Undergrad in the US isn't really worth the hype. People go to the US for undergrad primarily so that they may get a chance to settle. I have no such problem; with a US passport I can pop over any time I want with no trouble.