[wkyle]

> The answer to that more likely has to do with some very broad phenomenon: capital has been accumulating due to increases in energy availability. Human talent (that turns capital into something actual) is plateauing due to slowing of population growth.

> As the world became more stable over time, the default risk also lessened over time

I think these are both saying the same thing from two sides - the default risk going down doesn't really mean anything in isolation. The implied context is the default risk goes down for the same rate of return (or the rate of return goes up for the same default risk).