> People loyal to their country tend to stay there.

Not necessarily true. Source: I have friends and family who came to the US from Russia and are still loyal to Russia. When the topic comes up, they tell me they would fight for Russia in a hypothetical US/Russia war.

It's entirely possible to love your country and still seek out a better life elsewhere for practical reasons.

Edit: To clarify, this isn't universal. Some folks who came over absolutely hate the country of their birth, some still love it, while others are ambivalent. But you can't make a blanket statement like "people loyal to their country tend to stay there" when there are stark financial and quality of life advantages to moving from one place to another.