It's traditionally three generations, not six. And it's just human nature to look at things in a relative sense. If you are living a lot better than when you grew up, you are very likely to be comfortable and stop there. Similarly your parents might just be happy to see you reach that next rung, rather than pushing for more.
Immigrants doing it in one generation, working blue collar jobs while sending their kids to the ivy league or med school, prove it's not based on real barriers either way.
This is not about barriers (fortunately, most of us do not live in a feudalistic or caste-based or apartheid society, where this would be literally the case); it is about probabilities and effort, even when accounting for genetic differences.
It is extremely clear that our society, nowhere in the world, doesn't offer equality of opportunity; based on your birth, even accounting for genetics, your mid-life expected income could be predicted with decent accuracy.
> (fortunately, most of us do not live in a feudalistic or caste-based or apartheid society, where this would be literally the case)
It's great that you agree with me about barriers, but you might mention it to the posters in this discussion who are explicitly making claims of feudalism and apartheid. Beyond that, my post gave a logical explanation for probabilities. I don't see where you provided a counter to that logic, or even addressed what I said. How is my statement about three generations, for example, countered by your claim about predicting mid-life expected income for a single generation?
Immigrants doing it in one generation, working blue collar jobs while sending their kids to the ivy league or med school, prove it's not based on real barriers either way.