Almost every country in the world has fairly low social mobility at the top of the income and wealth scale. For example, the case of Florence, Italy came up recently in the news:
Gary Becker and Nigel Tomes concluded back in 1986, "Almost all the
earnings advantages or disadvantages of ancestors are wiped out in
three generations."
Barone and Mocetti show that, empirically, this is not the case, and
there is meaningful income persistence across seven centuries in
Florence. Their paper adds to earlier work by UC Davis economic
historian Gregory Clark, which reached a similar conclusion with
regard to Sweden going back to the 17th century.
They looked at 2011 income data to identity the five highest-earning
surnames in present-day Florence. They then looked back at 1427 data
to find information about the earnings and occupations with those same
five surnames 700 years ago. . . . They show here that the four
highest-earning surnames of 2011 were all above-average surnames back
in 1427. Indeed, three of the four were in the top 10 percent.
In the U.K., this is supported by Clark and Cummins, Surnames and Social Mobility: England 1230-2012, the abstract of which explains that:
To what extent do parental characteristics explain child social
outcomes?
Typically, parent-child correlations in socioeconomic measures are in
the range 0.2-0.6. Surname evidence suggests, however, that the
intergenerational correlation of overall status is much higher.
This paper shows, using educational status in England 1170-2012 as an
example, that the true underlying correlation of social status is in
the range 0.730. Social status is more strongly inherited even than
height. This correlation is constant over centuries, suggesting an
underlying social physics surprisingly immune to government
intervention. Social mobility in England in 2012 is little greater
than in pre-industrial times. Surname evidence in other countries
suggests similarly slow underlying mobility rates.
I am aware of studies comparing the pre- and post-communist regimes of China, such as this one, although the patterns of social mobility there, in this comparatively short time frame are more nuanced and complex.
But that doesn't really answer the question. The fact that descendants of people at the top tend to continue to stay at the top of the socio-economic pyramid for long periods of time, doesn't imply that people in poverty and dependent upon welfare stay in poverty.
Periods of sustained economic growth can "lift all boats" and take the poor out of poverty and welfare dependence without actually changing the socio-economic pecking order at all.
For example, China is the standout here. Reduced poverty rates in China over the last few decades have been the leading cause of a massive reduction in the extreme poverty rate for the entire planet. As the World Bank explains:
Over the past 40 years, the number of people in China with incomes
below $1.90 per day – the International Poverty Line as defined by the
World Bank to track global extreme poverty– has fallen by close to 800
million. With this, China has contributed close to three-quarters of
the global reduction in the number of people living in extreme
poverty. At China’s current national poverty line, the number of poor
fell by 770 million over the same period.
In general, it is challenging to disentangle changes in intergenerational poverty due to booms and busts in a country's economy from changes in intergenerational poverty due to changes in the degree of income inequality and relative social mobility in a given time period. Empirically, these factors are not independent of each other.
After a period of extremely high poverty rates during the Great Depression in the United States, World War II and the economic boom of the immediate post-World War II period (roughly coinciding with the Baby Boom) poverty rates fell dramatically from their Great Depression peaks for at least a generation. See, e.g., this review of U.S. income inequality and poverty rates from 1900 to 1990 (noting also that reduced income inequality can reduce poverty rates).
On the other hand, there are also studies in the U.S. showing that children of men who are incarcerated in prison are at a vastly elevated risk, of being incarcerated themselves during their lives.
Of course, at some point, you run into definitional issues about how to define poverty. If you define poverty on an income percentile basis, then it is mathematically impossible to reduce the total poverty rate and any policy that frees one family from poverty automatically and by definition, places someone else in poverty. In that scenario, intergeneration poverty could still be eliminated, by only by churning around who is all of the way at the bottom at least once twenty to thirty years or so.
On the other hand, if you define poverty in an absolute sense, defining a certain market basket of consumption and amenities to constitute not being in poverty (which is the more common way to define it), it is possible to result poverty, in principle anyway, through policies that make everyone more affluent.
At any absolute level of poverty, almost every developed country has reduced it over time. As late as the Reconstruction Era in the United States (i.e. the decade or so after the U.S. Civil War), indoor toilets and running water were uncommon in the American South, while half a century or so later, these amenities were almost universal in the same region. Complete illiteracy has fallen dramatically in every developed country. Deaths from starvation in the developed world have fallen steadily over time with the notable interruptions of the Irish Potato Famine and the famines in the Soviet Union and China respectively, following their conversions to Communism. Unlike the U.S. during the Great Depression, large portions of the population aren't dependent upon soup kitchen for daily meals. Pre-teen children no longer have to work in fields and factories to support their families in the developed world.
But arbiters of social policy tend to raise the bar for what is officially defined as poverty over time in that situation, complicating the inquiry into what poverty really means.
