I used to think that as well and it's totally true with most Chinese women (especially in poorer areas). However, I live in one of the most expensive city in China (Shenzhen) and I've met many women that were much richer than me, who have absolutely no intention of moving to cold Canada. At 8$/beer, the bars I frequent usually attract an upper class crowd (or women who have someone to pay for them).

Also, your theory doesn't hold in Hong Kong. Hong Kong is richer than where I come from and poorer women have a vast pool of rich men to choose from.