Billionaire-scale conspicuous consumption is certainly overrated. But Gates's own example shows how wonderfully useful and fulfilling it can be to have tens of billions of dollars to mobilize in a really heroic cause, like working to eradicate various infectious diseases from the human experience.

Just to get started, as long as we don't have clean water, plenty of food, proper healthcare, good education, meaningful personal freedom, and a well-functioning legal system for every human being in the world, cheap carbon-neutral energy, strong environmental protection and sustainable ecosystem conservation throughout the world, a cure for cancer, a complete genome and proteome and extended phenotype encyclopedia for all life on Earth, telescopes that can image Earthlike planets in other galaxies and the first stars to ignite in the extremely early Universe, robots crawling around under the surfaces of Europa and Enceladus and screaming through interstellar space toward Alpha Centauri and Epsilon Eridani, and human colonies on Mars and the asteroids and in the clouds of Venus, there will be plenty of interesting and valuable things to do for someone with tens of billions of dollars to throw at an ambitious project.