There comes a tipping point when the number of homeless becomes so great as to foster protest, rebellion, revolution, the collapse of government or at the very least changes in Administrations and policy.
During the Great Depression entire homeless neighborhoods or towns were named after the President; whose failed policies were blamed for the calamity and he was promptly voted out of office, to which his political party lost the White House for the next twenty years.
In Europe the consequences were even more devastating to their governments contributing to overthrow and eventually WWII.
http://en.wikipedia.org/wiki/HoovervilleA 'Hooverville' was the popular name for shanty towns built by homeless people during the Great Depression. They were named after the President of the United States at the time, Herbert Hoover, because he allegedly let the nation slide into depression. The term was coined by Charles Michelson, publicity chief of the Democratic National Committee.<1> The name Hooverville has also been used to describe any Tent city populated by the homeless in modern-day America.
Homelessness was present before the Great Depression, and hobos and tramps were common sights in the 1920s, but the economic downturn increased their numbers and concentrated them in urban settlements close to soup kitchens run by charities. These settlements were often formed on empty land and generally consisted of tents and small shacks. Authorities did not officially recognize these Hoovervilles and occasionally removed the occupants for trespassing on private lands, but they were frequently tolerated or ignored out of necessity. The New Deal enacted special relief programs aimed at the homeless under the Federal Transient Service (FTS), which operated from 1933-35.
Some of the men who were forced to live in these conditions possessed construction skills and were able to build their houses out of stone. Most people, however, resorted to building their residences out of wood from crates, cardboard, scraps of metal, or whatever materials were available to them. They usually had a small stove, bedding and a couple of simple cooking implements.
Most of these unemployed residents of the Hoovervilles used public charities or begged for food from those who had housing during this era. Democrats coined other terms, such as "Hoover blanket" (old newspaper used as blanketing) and "Hoover flag" (an empty pocket turned inside out). "Hoover leather" was cardboard used to line a shoe with the sole worn through. A "Hoover wagon" was an automobile with horses hitched to it because the owner could not afford fuel; in Canada, these were known as Bennett buggies, after the Prime Minister at the time.
After 1940 the economy recovered, unemployment fell, and shanty eradication programs destroyed all the Hoovervilles.<2>
The question becomes, must the world's societies continually experience those catastrophic events or can they evolve to provide basic living essentials to all their citizens even the individually weakest members and avoid such extremes?