Traffic on 57th Street in Manhattan is as busy as usual, but new to the mix of yellow cabs and black town cars are the many heavy trucks that are shuttling material to several construction sites where New York’s soon-to-be tallest buildings are set to rise. In fact, two new skyscrapers have already risen: the 1,004-foot-tall One57 (or 157 West 57th Street), a cascading blue, gray, and silver glass-clad tower designed by Christian de Portzamparc for a midblock site across from Carnegie Hall, and to the east, on a block-deep site between 57th and 56th streets, the 1,396-foot-tall concrete-frame 432 Park Avenue, designed by Rafael Viñoly. At these heights they call attention not only to their forms (which are more visible from a distance than from 57th Street itself) but also to the extraordinary prices these so-called supertalls are commanding for condominium apartments with Central Park views: $100.7 million for the duplex penthouse at One57 and $95 million for the penthouse at 432 Park, where the average apartment price per square foot is $7,000. A panoply of media, from The New York Times Sunday real estate section to the online real estate newsletter CurbedNY, regularly reports the highest price paid for a residential property each week, which in Manhattan today is seldom a number less than eight figures (and not just with park views, but in many neighborhoods)...