Country B might have: a better political system, less war, more money, better treatment for some group one’s part of (women, gay people, intellectuals, Sikhs, …), less disease, nicer climate, lower taxes, better public services, better jobs, better educational opportunities.
Other than climate and to some extent money and war and disease, these mainly depend on which kind of people Country B has.
Other than climate and to some extent money and war and disease, these mainly depend on which kind of people Country B has.