Why is it that outcomes are not the same? Most poor folks remain such, and live their lives pro-creating young, etc. A minority of them overcome the situation

Why is it that outcomes are not the same? Most poor folks remain such, and live their lives pro-creating young, etc. A minority of them overcome the situation given the circumstances presented: if it is a country in dire straits, they immigrate out. If it is the U.S. or another rich country, they make it work. In places like LA and NYC and Chicago, there are immigrants who made it, poor who made it and poor who didn't.