We can't just assume "public goods" like national defense benefit everyone. They come with real costs, and all the "services" that fall under the category of national defense are certainly not of equal use or benefit.
In the blurry world of conflicting economic indicators and forecasts and policy surprises, activist policymakers at the Fed do not know exactly what the “right” monetary policy is today. Neither do their activist critics.
People do not save and accumulate capital because there is interest. Interest is neither the impetus to saving nor the reward or the compensation granted for abstaining from immediate consumption. It is the ratio in the mutual valuation of present goods as against future goods.