Norman Borlaug is the first person that I thought of as a millionaire superhero because when he died in 2009, his obituaries usually credited him with saving millions of lives or even a billion lives. He and his teams of fellow scientists accomplished this through simple selective breeding of wheat and other crops. Selective breeding is a practice as old as agriculture, but it was mostly just a haphazard part of saving seeds for planting the next crop for most of history until it was transformed into a methodical system using the scientific method in the last couple centuries. Even so, before the advent of the scientific method, primitive societies accomplished incredible transformations of wild plants over thousands of years. For example, Native Americans in Mexico turned the humble wild teosinte into the mighty maize.
Norman Borlaug simply applied scientific selective breeding to improving the crops of the tropical regions of the globe where poor people mostly live. It wasn’t a terrible complicated task compared with genetic engineering, but it required a lot of painstaking work and financial resources to fund a dedicated effort. Seed companies in the temperate parts of the northern hemisphere had been doing the same kind of intensive selective breeding for decades, but nobody had applied those modern techniques to crops for tropical regions until Borlaug’s lab began the Green Revolution. Thousands of scientists have had a part in this revolution such as Robert F. Chandler, and many other recipients of the World Food Prize and the Wolf Prize in Agriculture, but even the biggest superheroes like Norman Borlaug are mostly unknown.
Their work continues to improve life in both poor nations and in rich nations like the US. Over the past half century, these superheros have been reducing hunger around the world and in the US they have reduced the percent of income that Americans spend on food.
Matt Yglesias at Vox created this graph using USDA data, and unfortunately the USDA doesn’t look at the percent of the median disposable income that is spent on food in the US. That would not look as good as this graph because of stagnant median income in the last few decades, but median income rose briskly in the 1960s, so the first part of the graph would still show great progress.