In addition to Poly’s observations, my initial point regarding having a same-community network still stands. The Italians and Jews who stepped off the boats in 1907 had multiple places to go in the five boroughs (plus New Jersey) to find people speaking the same languages the moment they got off the island. Poles generally had destinations in (and often train tickets to) Buffalo, Pittsburgh, and Detroit. Serbo-Croatioans and Slovenians had communities in Cleveland, Italians in most major Great Lakes cities, Norwegians in Minnesota, Germans in Pennsylvania, Wisconsin, Texas, and most Great lakes cities.
In addition, there were millions of factory jobs calling for unskilled labor. As people saved money from jobs in the New York/New Jersey region, they used that money to buy tickets to move to the factories of the Great Lakes region, the mines of Pennsylvania, West Virginia, Michigan, Minnesota, and Colorado, and the farmland across the Great Plains. And each family who moved West opened up one or more factory positions at the points where the immigrants were landing. And, as Poly noted, the factories were generally built in the middle of the neighborhoods from which they drew their workers while street railways and subways provided a network of transportation that was intended to take people to and from work. Current freeway systems are designed to do the same thing, but the destinations are much farther apart and require the possession of a car. (New Orleans, prior to Katrina, had a higher percentage of people who did not own cars than did New York, meaning that the dispossessed are very unlikely to have transportation.)
Beyond that, while immigrants lacked the Federal safety net (such as it is) that currently exists, local governments and private agencies spent enormous sums on settlement houses and similar establishments that were intended to bring immigrants into the mainstream as quickly as possible. It is interesting that you picked 1907 for your figures: USES [U.S. Employment Service] established as Division of Information in the Bureau of Immigration and Naturalization, Department of Commerce and Labor, by the Immigration Act (34 Stat. 909), February 20, 1907, to distribute immigrants throughout the United States.
If Houston was still an oil boom town, those 700,000 families might have been swallowed up in the prosperity and jobs of the region. I have yet to see evidence from the Houston Chronicle that there are 700,000+ jobs available in Houston.
Again, I have no problem with anyone initiating efforts to get the NOLA displaced persons on the road to self-sufficiency. I object to the false claim that everyone who has suffered, previously, did the same for themselves with no help. It is simply not true.