When Philadelphia's iconoclastic city planner Edmund N. Bacon looked into his crystal ball in 1959, he saw a remarkable vision: "Philadelphia as an unmatched expression of the vitality of American technology and culture." In that year Bacon penned an essay for Greater Philadelphia Magazine, originally entitled "Philadelphia in the Year 2009," in which he imagined a city remade, modernized in time to host the 1976 Philadelphia World's Fair and Bicentennial celebration, an event that would be a catalyst for a golden age of urban renewal.

What Bacon did not predict was the long,...