There was a mood of reverence in the New York Public Library on Monday as the world’s two wealthiest men met to announce a landmark development in charitable giving. It will soon need to be converted into much more down to earth action.

Bill Gates, whose “new economy” software business has generated him a personal fortune currently estimated at $50bn, may not appear to have much in common with Warren Buffett, the “sage of Omaha” whose focus on “old economy” investment has made him $44bn.