It’s interesting to read these (plausible, far from absurd) analyses from the Anglosphere when we have an alternative to compare, to whit the northern European democracies where marriage is in steep decline across all social classes yet the societies are more successful (at least if your metrics are things like poverty rates, lifetimes, nutrition, stress, etc).
I think missing from this comparison is that while the US is quite different from Finland, New Hampshire when taken on its own is quite similar. But we never ask, “how could we make the whole US like New Hampshire?” and probably for good reason! I don’t think we’d want the whole US to be that way. The US is big and diverse and that’s a good thing.
US diversity is not uniformly a good thing. It may be a good thing when it comes to positive examples of successful communities, but breakdowns in education, low income support, and wilderness management systems are apparent in all of our states and territories. The US should absolutely be adopting competent successful approaches from its union members at the federal level, even if it makes us all a little less distinctive and a little more New Hampshire.