is available to commoners in other countries and the very real cultural barriers to outsiders or even caste type systems with their own citizens.

Japanese culture is not at all open and there is definitely a caste system.

India. Worse.

Vietnam. I have no personal experience. But security?????

Philippines. I know a family that did get very rich off the backs of cheap labor in factories there. The wife was from there and had family there. Did they live there? Heavens no. They visited on business and for leisure - but they lived in Hawaii and still do. Why? Schools. Security. Weather. Socialization. His brother was in Finance and made a fortune in Japan. Did live there for a few years. He moved to Hawaii as well. Japanese and Chinese ethnicity are the most common in Hawaii. There are reasons they are there instead of in China or Japan. Lots of Koreans and Vietnamese as well.