In much of the developed world, economic productivity seems to correlate strongly with availability of free capital (I don't have a source but I imagine it's fairly straightforward to cook one up). Even US vs Europe, kind of similar economies, but with capital so much easier to come by in the US, and US productivity per capita is flying compared to Europe.

Availability of free capital is a function of both just general wealth of a society, and how well lubricated the wheels of finance are.

I don't think this is a controversial theory, even if it comes with unpleasant side effects (white collar crime, inequality etc). Just as having a buoyant defence industry that can churn out a lot of boom is great for a country's war fighting potential.