alt Hacker NewsIt doesn't really matter what the business is, farming was an example but if you need a concrete example of a billionaire that started as a farmer and built his fortune in agriculture and ag related business then look to Harry Stine[0]
There are plenty of other billionaires that started as small business owners putting in their own work. They became billionaires by successfully managing their business and scaling, expanding and pivoting it. There are also ones who derive their wealth strictly from investing or purchasing other businesses, maybe that doesn't seem like work or seems unfair for some reason but you can't just take a random person and hand them millions of dollars and expect them to turn that into a billion dollars. Most would go bankrupt if they tried, smarter ones would just be low risk millionaires living off interest or broadly diversified investment returns. To me, those ones would be the only people I'd say aren't really earning their money but if it's their money then it's their choice what they do with it.