People became more productive due to technology. Now you are able to produce enough for you and your family in 40 hours / week. Before this technology advancement, you needed to work 60-80 hours / week in order to produce enough.
WTF are you talking about back in the first half of the last century, unless you worked on the farm, you were able to produce enough for you and your family in a 40 hour week with just one adult working and that was with an average of 4 kids. Today, it takes both parents working with an average of 1.4 kids.
Technology may make us more efficient, but it has nothing to do with the economics of providing for a family.
Jobs are not a scarce resource, labor is. There is always enough jobs for everyone that wants one and then some, even if it means being self employed. The only reason there is unemployment at all, is because of bad laws.
For a look at what really happened to America's jobless when manual labor jobs disappeared, check out a collaborative NPR Planet Money/This American Life expose on this invisible economy: "Unfit for Work: The startling rise of disability in America" The program's podcast "Trends with benefits" is well worth listening to.
In summary, what happens is that manual labor jobs disappear from small American towns and they're replaced with lawyer and bureaucratic desk jobs in large cities, state capitals and Washington D.C. A look at trends in unemployment during the great recession gives us a glimpse of this. But Americans on disability don't appear in any labor department unemployment or employment statistics. What's more, people on disability almost never get off the program. Unlike welfare, people on disability are discouraged from working, their kids are discouraged from doing well in school. Even in comparison the obvious economic mess made by programs to promote debt until death (aka mortgage), the non-productive trillions in the derivative economy, this 200+ billion dollar hole in the US economy is significant specifically because of its social fallout. Uncovering this is the first step in adjusting our economy to a new reality of labor and employment.