I am aware of today's inequality (e.g., I read Piketty back when he was making a splash). But the critique is that Greenspan argued gold standard = less inequality and that fails on the historical record.

If we want to talk about the causes of the 'New Gilded Age' that's something else. As a general starting point I'd begin with:

* https://en.wikipedia.org/wiki/Friedman_doctrine

* https://en.wikipedia.org/wiki/Reaganomics

* https://en.wikipedia.org/wiki/Thatcherism

Yea, that's his point. The gold standard neither prevents nor encourages inequality, except inasmuch as it limits policy flexibility (which, similarly, could be used to promote or limit inequality).

Don’t those two data points suggest inequality is orthogonal to the gold standard?