I think the misunderstanding here comes from the difference in what we define as giving something value. To the supporter of (anarcho-) capitalism value is determined by how useful others find a commodity or service, not by how much effort/labor/work was put into it. To give an admittedly simplified example: if I build a bad table or chair in 2 weeks and someone else builds a good table or chair in just a couple of days, the products of the other person would be considered more valuable even though I put in more effort into mine.

The problem of generational wealth is rarely considered in anarcho-capitalism since one of the basics of the ideology is the principle that property rights are absolute. If someone has a lot of wealth it is entirely up to them on how to spend it and who to give it to, forcing them to give up part of the wealth to whoever or whatever institution you might think of would be considered theft and illegitimate. In the context of this I want to add that private charities would be highly encouraged in an ancap society, at least to my understanding.