Speaking from experience of my late wife's family was to give the next generation the chance to grow up with more freedom and more choices.
Yes you are right most of them are upper or middle class professionals with a education in China. The come here hoping to pick up there life in relatively the same place they left it in China. Problem is the lack of North American experience or so it is claimed. The majority upgrade their education or start their own businesses or just get a job within their community. Those that do upgrade their education do not get top jobs and see promotions as a very slow and patient process. With the majority of our professional work force in the 45-60 range the chance of getting the corner office slips away for 10 or 15 years. Meanwhile the world economy is knocking on China's door these new comers to Canada have North American education and experience as well as speaking Chinese. What happens is they can move faster and get a better life in China. But they do not give up the Canadian citizenship for themselves and their children.
Who can blame them i would be making 60 to 70 grand a year still if i had not left and gone out on my own to work.
If i had the chance i would move to China and do what i am doing making relatively the same amount of money but because i am in China i can live like Trump(or is chump).
The quality of life is balancing world wide for the middle class which in some countries live more like our upper class.
When i worked and lived in Karachi i was making about 35 grand american a year but i had my house and car and driver and maids all paid for by the company.