Why welcome people who run from problems rather than fixing them--especially when many are of considerable wealth, and are disproportionately responsible for th

Why welcome people who run from problems rather than fixing them--especially when many are of considerable wealth, and are disproportionately responsible for the unsatisfactory condition of their own countries? If we shut the door on wealthy Chinese/Indians/Saudis/Nigerians/etc, I'd bet big money that the condition of those countries would improve rapidly and substantially.