I'm sorry - what is the diffuse societal benefit' ?

Do you to mean to say children are a diffuse...., or something else?

Surely it is clear to one and all that low low fertility rates now = no children very soon = no people just after that = end of human life

Or is that 'diffuse' ?

In which case a lot of people should get a grip - as the article suggests these no children people might be replaced by the arch conservative many children people, currently a small minority, but perhaps soon ish a large minority/majority

Then it'll be a very un diffuse benefit, if you can't lick 'em join them type stand off