re: The goal of many Gen Z and millennial women is now to be a DINK—dual income and no kids

That's not really it either. His was a pretty standard retort to the "if you haven't lived the experience, you can't observe or comment on it" and it has nothing to do with parachutes or being cared for when you're old. It's a logical fallacy that consistently falls apart with almost any rebuttal. And, most importantly to this topic, it works for any side of any debate in the context of "lived experience" and no use of the argument is more or less valid than any other.

On a related note, if you put a 40 year old parent and a 40 year old childless person at a table, only one of them has lived both with and without kids. And exactly none of them have grown old without kids. For whatever that is worth to the "lived experience" prerequisite.