When large numbers of uprooted people collect in one place, they don't just live in disorder. A separate local community grows up to meet their needs, with its own economy, social life, politics, codes of conduct, language and customs.
Seasonal and boom work, such as railroad building, new mines, oil strikes and big harvests, draws thousands of new recruits each year into wandering labor. Because the work itself is seasonal and cyclical, you cannot deal with the homeless man as an individual without dealing with those economic swings. That also makes the problem national, not local.
Every large city has a district that homeless and migrant men drift into, known on the road as the "main drag." It sits right next to the commercial center. It works as home because, however bad a man's situation, he can find others there who understand it.
The number of homeless men in a city rises and falls with the economy, more than doubling between good times and hard times. Far more men pass through each year than stay at any moment. This shows the population is a moving labor pool rather than a fixed group of individual failures.
The same restless temperament that made a man a valued pioneer on the frontier gets him labeled a homeless vagrant in the modern city. The person hasn't changed, only the setting that judges him. In that sense the city is now making men as much as men once made the city.