Even granting that the real source of the increase is the free market -- things like the miracle of compound interest, or the ability to invest in growing industries and factories and the like -- the premise leaves out something very important about how one obtains the capital to make such initial investments. Let's say that, due to these economic miracles, we could become rich with an investment of merely $100,000 -- that this will produce an increase like she's discussing, so that it will become worth $2,500,000 in time (and that will continue to grow).Yet I do not have an extra $100,000 to invest. If, however, there is a legal and successful way for me to rob another man for it -- taking it out of him in labor, or a legally contrived way of stealing his house, or whatever else -- then I can make the investment. And then I will become rich, and my descendants even richer! He will become destitute, and his descendants will not enjoy the increase in wealth that mine do. They may become better off if 'a rising tide lifts all boats,' as they may become well-paid servants of my descendants. Nevertheless, the initial theft really matters and produces long-term differentials in wealth and power.
America's South has long been its poorest and most benighted region, but this was not always the case. Before the Civil War, it was a tremendously prosperous region. This was driven by one of these forms of stolen wealth too, the slave system, whereby a man's whole life of labor was plugged into investments by another man who stole it.
There are some other theories about why the former slaves had such positive things to say about their lives on the plantation. The one to which I am most inclined is that they were all much older when they gave the interviews, and spoke with the natural nostalgia of the old for the sunny days of youth. Memory paints the memories of those days, in nearly all of us, with rose colors.But there are other possibilities too. For one thing, economic conditions in the South cratered after the war, so that life after the war was markedly harder for everyone -- especially, as is usual, those on the bottom. The traditional market for Southern cotton was lost, as the English mills had turned to India during the war's blockade. The South's mills were destroyed, so it was relegated to being a producer of raw materials for Northern mills at rates set by Northern banks. The economic system imposed by the North was a brutal colonial-style monoculture built around cotton production, and colonial monocultures are notoriously harsh places to live (here as in Latin America, India, and elsewhere). Until the boll weevil collapsed the cotton economy in the late 1920s, the South was ground down by the usual effects of such economies: the price of the monocultural good (cotton, here) dropped every year, because supply increased every year as those commanding the economy forced ever-greater production of the single cash crop. Under those circumstances, quality of life dropped, again especially for the poorest and those most dependent on agriculture. Naturally those who had been slaves who had only known how to work cotton farms, or who were directly descended of slaves who had, were very likely to be a part of the very lowest agricultural classes tied to the cotton monoculture. They would have endured the worst conditions imposed by the economic system.So it is possible (indeed it doesn't seem unlikely) that happiness is greatly influenced by economic realities. When the interviews were conducted from 1936-8, the boll weevil had collapsed the cotton economy, and the Great Depression had followed on its heels. While the boll weevil eventually allowed the South to escape the monoculture economy, at first it meant a severe economic depression for the region, which was then followed on by a severe depression worldwide. The former slave speaking in 1937 would be looking back on a life that had, in economic terms, ground ever worse each year of his or her life, capped by ten years' complete economic failure. The pre-war plantations may really have seemed like a better place by comparison to that. They may really have been, if not a better place, a happier place.