I don't think that this is true in the United States. People do acrue wealth over their lives. I don't know where you are talking about, so it is quite possibility true for there.
This site breaks it down by age, and not as a simple average:
https://wealthvieu.com/personal-finance/net-worth/net-worth-by-age-percentile/
Anyway, if you are correct and retired people have no money then you disagree to the original post, since the whole thesis is that older generations are taking wealth from the younger generations!
I basically agree with that interpretation, since I think the main divide is capital versus working class.