In Denmark, we know every economic event of a person's life. But I assume you also know something about their parents income and so on. The family is playing a very important role, but it's not one thing you didn't mention in your dialogue. There are ways that children can shape the lives of their parents throughout 20 years.
Economist and Nobel Laureate James Heckman of the University of Chicago talks about inequality and economic mobility with EconTalk host Russ Roberts. Drawing on research on inequality in Denmark with Rasmus Landerso, Heckman argues that despite the efforts of the Danish welfare state to provide equal access to education, there is little difference in economic mobility between the United States and Denmark. The conversation includes a general discussion of economic mobility in the United States along with a critique of Chetty and others' work on the power of neighborhood to determine one's economic destiny.