Cities are predicated on a set of trade-offs that no longer make sense. Middle-class people tolerate density, pollution, disease, crime, high taxes, and expensive housing to access superior employment opportunities. If comparable opportunities can be accessed without the above costs, many people will opt-out of the current arrangement.

Zoning is losing its power. New ventures are able to reach a meaningful scale before regulators (and competitors) react. The boundaries between different uses are blurring, with people lodging in apartment buildings, living in hotels, working in restaurants and retail malls, and sleeping or socializing at the office.