Let me put this in a simple term that everyone can understand.

Not all the people from vietnam countryside or small towns want to leave their birth place to go the big cities (such Saigon, Da Nang, Hanoi, etc ...) to start a new live. People leave because they either are sick of it, discriminated or have nothing else to live for.

And when they come to those big cities (such Saigon, Da Nang, Hanoi, etc ...) they have to start their new life all over again (it's difficult and may take a long time to settle down).

Well now you just take that theory and apply it onto "coming to American for a new life" thingy, you will understand.

If you are a lazy bum then "coming to live in a big city in VN" or "coming to live in America" is not for you. Just stay where you are now and enjoy what "XHCN" offers.