Or, in other words, how much will you deprive your own society of and contribute to American society, assuring our domination and your society's dependence and subjugation.
Human beings are not property of their governments. They have a right to live, and move to a place that they choose. Brain drain might be a problem, but the correct approach is to make the drained country a better place to live, not to prohibit escape.
It's sad that people don't realize that or value the contributions they could make to their societies, to lift their cultures and countries, instead of compounding ever more advantages. It's brain drain. It's rather supremacist in nature too and not unlike colonialism.
I'm not planning on going to America because a) I'm more interested in seeing other places (sorry) and b) It's impossible anyway. But let me tell you something: When I leave, I won't be depriving "my own society" (whatever that means) of anything, because that's how much value I can produce here, with all the corruption and bureaucratic obstacles.
And it will remain so because all those who could possibly affect change are taking the easy road to America and compounding our returns and advantages.
Frankly I'm only thinking about moving to the US because my girlfriend is American. She has a lot of debt from her studies and she works in education, and education pays a lot mainly in the US. Basically she needs to rip some other students off to pay her debt, it's a pyramid (I hope she doesn't red this).
But I'm not attached to my country, the country I was born in is an accident, they are conservative and short sighted, I don't care leaving (albeit, I don't think the US is really the best place to live).