[mrkeen]

The article says that young people are poor, old people are rich.

Parent comment claims that young people are not having kids because poor.

Your graph says that richer people had fewer kids (in the last 12 months).

Your graph would only refute the parent comment if you could show that people have fewer kids because they're richer, not because they're older (confounding factor) and/or people with more kids don't have to sacrifice an income to look after said kids (reverse causation)