In his defense it was a joke. “Krugman said it was part of a piece he contributed to New York Times Magazine in 1998:
It was a thing for the Times magazine's 100th anniversary, written as if by someone looking back from 2098, so the point was to be fun and provocative, not to engage in careful forecasting; I mean, there are lines in there about St. Petersburg having more skyscrapers than New York, which was not a prediction, just a thought-provoker.”
– Bill Gates, 1970s
It was a thing for the Times magazine's 100th anniversary, written as if by someone looking back from 2098, so the point was to be fun and provocative, not to engage in careful forecasting; I mean, there are lines in there about St. Petersburg having more skyscrapers than New York, which was not a prediction, just a thought-provoker.”