While some of you may not view New Zealand with the admiration that you view the US, as its tech-scene isn't quite as developed. It is a beautiful country nonetheless, free healthcare is available for all residents and citizens, not to mention the all around natural beauty of it.
Don't get the wrong impression, there is no doubt that the US is a great place, but it isn't without its problems. I'm not trying to sell you on NZ, the point I'm trying to make is why should I have to bust my balls and save up $100k for a green card when I can have more lenient and reasonable terms in another country with an emerging tech scene?
Note: it is probably easier for entrepreneurs to supply $100K for a green card, however, I intentionally ignored that circumstance as they're a minority amongst immigrants and chose to discuss immigration to the US in general.
Bottomline: America unknowingly abuses and doesn't treat immigrants with the respect that they deserve, they contribute equally to the economy as any other demographic (if not more), and are a major part of high tech industries, and therefore, of the US economy.