That was because being in US was considered a status symbol until recently. Parents used to feel proud to tell their friends and relatives that my son/daughter is in US, even though deep down they are afraid of ending up alone. I see an Indian eagerly waiting to be picked for the H1B visa similar to the Sausage Party movie where they all wait eagerly at the supermarket thinking outside the door is heaven or something. I agree some of the things (especially pay) are better than in India, but they are loosing a lot. And India is only going to get better (probably in another 10-15 years, lot of things in India will be comparable to what US has currently).

Coming back to the parents, now with all the negative coverage of H1B in Indian media, people have a negative perception of being in US. My visa expired and is in process of renewal. I didn't go to office one day. My dad thought I wasn't going because I was hiding from the authorities since my visa expired. They have been asking me to come back for a while now.

600K Indians out of 1 billion is nothing. Huge number of Indians don't want to leave India. I hope you know that. It becomes more evident once you are in the marriage market. Lot of them are downright reject proposals from people who work in US. Also, I never heard of Canada immigration until 1 year back. Now, a lot of my friends/colleagues are talking about or in the process of applying for the Canadian visa.

And a good number of those who apply for green card don't do it because they want to become a citizen. Its because once you complete a certain stage of green card (I-140), you can continue working in the country. Otherwise, you have to leave once you complete 6 years. They plan to work for 10-20 years, and come back to India and retire nicely with all the money they made in US.