China has more than enough people.
Japan and Korea homogeneous, the people won't accept outsiders as some of their own kind.
I'm residing in Singapore. Hmmm, there is nothing called retirement here. Many old uncles and aunties work as cleaners in food-courts and canteens around the city to support their living. Immigration system here is race-based (well, no one wants to talk about this). If you are non Chinese, you will need a lot of luck.
Vietnam, hmmm, trust me, we will try every chance to get out... This is sad, but true.
This may change in the future. But if Canada is still a choice, I would say let us go for it. I could have immigrated long time ago, but I thought, maybe one day I can get to settle down here in Singapore. But that day is just getting more and more vague.