Starting another plumbing business is very unlikely to net you a billion dollars. To achieve that you need to bet on riskier businesses, they are more likely to

Starting another plumbing business is very unlikely to net you a billion dollars. To achieve that you need to bet on riskier businesses, they are more likely to fail. If your parents are well off you can afford to fail a few times by betting big. Most still won't succeed but it doesn't affect them that much because they're insulated from the downside risk due to well-off parents. My point isn't really that people from well-off families are more likely to start a family, although that probably is true as well. My point is that people coming from a regular background are more likely to start less riskier businesses, less chance of failure but also less chance of reaching a billion dollars.