I doubt they're going back to China or India. Far more likely is that they're coming to Canada or going to Australia or Europe.
We have tons and tons of Chinese people coming to Canada to go to school. It's not a stretch to see them setting up shop here after they graduate. Wealthy Chinese families recognize how safe they are in the West. They don't mind paying high taxes to get away from the CCP.
In any case, it's not just having talent go to developing countries that I see as a positive, but also seeing other countries' increasing tech scenes. I think having geographical diversification in the tech world is healthy. For starters, if one country ever elects a leader that wants to attack tech and automation as aggressively as the US leadership is attacking immigrants, then human technological progress will be less affected.
I imagine it's a boon for those developing countries. Instead a natural brain-drain, the country doing the draining is stopping it. I'd love to hear some stories about entrepreneurs who wanted to come to the US, but had to go elsewhere and ended up building large businesses. I do see a lot of cool startups coming out of India (that we use for our startup, like Chargebee and VWO) - I wonder if they would have been tempted to start them here in the US if it were trivial for entrepreneurs to enter.
Perhaps a rare case of the road to heaven being paved with bad intentions.