A few years back, there was a lot of buzz about Warren Buffett’s monumental donation to the Gates Foundation. It deserved that buzz, because it was (and remains) the largest charitable contribution of all time. But it was also remarkable because it amounted to the second-richest man in the world (now third) giving the bulk of his wealth to the richest man in the world (now second), who, in turn, left the helm of the company that he built in order to pay more attention to the best way to give away the bulk of their combined wealth. But...