How do countries without large immigrant (I won't even go to refugees) populations handle this? Switzerland seems to be doing fine. Japan isn't falling apart because there's nobody to cook. Most of Asia is doing fine without allowing any immigrants.
So on a strict analysis of whether immigrants are beneficial to the host population, your argument isn't made.
2. All the talk about Japan economy doing badly is nonsense. If you believe that narrative (which is totally understandable as that's the conventional wisdom), I strongly suggest you read this article: http://www.nytimes.com/2012/01/08/opinion/sunday/the-true-st...
Basically many Japan watchers (ie people who live there and know the country intimately well) subscribe to this 'alternative' view.
1. Some inconvenient Swiss immigrants aren't immigrants.
and
2. Read this article from 2012 and ignore the last 4 years of Japanese GDP. (http://www.tradingeconomics.com/japan/gdp)
Care to try again?
Engage in discussion people. Downvotes are for quality, not disagreement.
I cannot figure out how to get an answer to this.