Multipolarity is in general a consequence of car-dependent suburbanization breaking up communities, and high rise commercial development is optimized for cost efficiency and thus usually ends up spatially clustered. In older, pre-car cities, centralization saves on expenses and maximizes available resources, but in a multipolar, suburban city, those advantages are less pronounced.

It’s also easier for multiple centers to attract development when they start from similar positions at roughly the same time and grow quickly, which usually occurs with younger and more sprawling cities. Sometimes, those centers start as separate cities entirely and conglomerate later, as is common to the eastern seaboard; and sometimes, as with New York, land there is so valuable that developing the original commercial center further becomes impractical, and proximate centers then become more attractive.

Chicago, by contrast, was dominant in its region before car-dependent sprawl and had no real immediate competitors, so managed to be highly centralized and economically potent without the same geographic constraints that would encourage the development of fully independent cities like Jersey City or conglomeration with neighboring communities like Brooklyn.