(Part 1 of 2?)
There came a point when the exponential growth of the world's population exploded. The need to provide shelter overtook the planning of cities and out of necessity they grew into unprecedentedly dense megacities. As mile high towers quickly replaced parks and public plazas, leaving the street as the only remaining public space, the city became increasingly introverted, uncouth, and hostile. The street became an urban canyon, and was referred to as such. In the distant past, expensive cars, jewelry, and other material possessions were the symbols of wealth. That changed as open space became the most valuable commodity, and people protected it proudly. Balconies, roofs, and the extremely rare backyard were akin to gold and eventually even became legal tender.
Developers and large corporations that could afford the investment built privately owned public parks on the roofs of their sky scraping structures, a government sponsored incentive to improve quality of life (essentially the government was giving it's wealth to corporations for the right to provide space). Yet as this practice became commonplace and lobbyists over time managed to deregulate the system, it became apparent that corporations could increase their wealth by bulldozing buildings to build in their place nothing at all.
The empty lots stood there boasting their wealth in the city, surrounded by tall barbed-wire fences, the mile high buildings, and KEEP OUT - PRIVATE PROPERTY signs. Constantly illuminated and surveillanced, the shrines to abundance were prisons of nothing.