The company’s pony-tailed owner, Rob Baan, greeted us at the door. In a hothouse off the lobby he fed us samples of tiny chrysanthemums, shiso leaves and a flower whose name I failed to catch that he said was used in toothpaste, which instantly anesthetized my mouth for several troubling minutes.

Mr. Baan then led us through airlock doors into the iridescent greenhouses.

A dozen-odd years ago, the United Nations announced that this is the first urban century, the first time more than half the world’s population lives in cities. Predictions were that some 70 percent of humans will be urban-dwellers by 2050.

Having been left for dead a generation ago, cities suddenly became the next big thing. Books and biennials about cities flooded the architecture world. As Mr. Koolhaas says, the focus on urbanism “gave people the right to ignore the countryside,” incubating a “reservoir of indignation” — although it’s not quite clear whom he means by people. The people who turned out for Trump and Brexit certainly never forgot about themselves.

Along which lines, this is the sort of show that may invite charges of slumming by a world-famous architect who, it is said, often gives off the imperious, slightly impatient impression that he has something better to do. At 75, tall and imposing, given to a uniform of gray and black slacks and mock turtlenecks, he can seem almost comically restless. When I chat with his friend Ms. Boom, a warm, exuberant character, before we all head out for a Japanese dinner in Amsterdam, he paces her house like a caged tiger.