I would guess the opposite, society needed a much larger share of its workforce for basic necessity. So assuming that the different opportunities to build somet

I would guess the opposite, society needed a much larger share of its workforce for basic necessity. So assuming that the different opportunities to build something were similar, only a smaller fraction of the possibilities got actually build and this fraction had the highest return of investment. So expected ROI was a lot higher and therefore the creditors could ask for a lot more interest.