For a fleeting moment this spring, New York City actually feels like that famous 1976 Saul Steinberg cover for the New Yorker—the one that captures the now-faded solipsistic conviction of the city’s residents that nothing of significance happens beyond their little island. “View of the World From 9th Avenue” looks out west at a flat, anonymous planet that exists unknown across the Hudson River, the vast empty plains beyond “Jersey” dotted with little settlements like Kansas City and Chicago, as the alien nation beyond the metropolis diminishes with perspective toward a Pacific Ocean narrower than the three blocks between the...