>>5
What proof have I got? Well, I worked on a fishing boat in alaska for 2 years, 2 or three months at a time. Most of the time I was the only US-born person in a fish processing factory full of Vietnamese, Koreans, Poles, and Latinos. After a while I got promoted to deckhand, just because English is my first language, and communication with the guy in the wheelhouse is crucial.
I saw american college kids (and a few Japanese) get on the boat in early summer and try to endure a 2-month contract. Most of them bagged out after a few days and had to ask mommy and daddy to wire them money to pay for their plane tickets back home. The ones who made it through their first contract, and came back for a second, usually moved up into engineering or something. By contrast, the majority of the immigrants stuck it out and stayed down in the factory simply because they had (and probably still have) few other choices.
Do you plan on immigrating to China to work on a farm or on a factory production line? I wouldn't advise it, but if you did then yes, you would most likely find yourself working much harder and for a lot less money than you do now. No, if you are a white person from the US you wouldn't go work in China unless you had some kind of white-collar job waiting for you. Or unless you're some kind of humanitarian worker.
In summary, anyone is capable of working hard. But anyone who can get a cushier job and get paid more will do so. That leaves our factories and fields full of immigrants, criminals, and dimwits.