Birth order science by mutual commiseration

I've been asking around in my social circle, and have come to a scientific hypothesis, backed by empirical anecdotal evidence.

In two-child families where the children are the same gender and the age difference is 2-3 years, when the younger sibling gets their first grown-up job, i.e. their first job in the field in which they ultimately aspire to work, they begin talking to their older sibling as though the older sibling is an ignorant, misbehaving child and the younger sibling is the only person in the whole entire world who is aware of How The World Works and How Things Are Done. This behaviour seems to occur regardless of the older sibling's life situation.

I'm hoping to gather more evidence about how this works in mixed-gender families and families with more than two children.