And they didn't even provide data to support that this single incentive explained anything.

Why not at the very least least compare marriage data across countries with different child support laws?

This is a really frequent thing that I see in current events / social policy / social trend analysis...there's a lot of great thinking by clearly smart people but it's on very slim supporting evidence - even when evidence is available it's not used.

Really, is there anything that should cause us to privilege this hypothesis over something simpler - like, for example, increasing affluence tends to delay age of marriage and prolongs "childhood" in terms of earning?