"Should investors worry about the mass money printing by central banks? Certainly. It has distorted financial markets and inflated prices across asset classes. But perhaps this simply leads to lower future returns rather than higher inflation."

This seems self-contradictory. Why is asset inflation not a form of inflation? Or by "inflation" do you mean CPI? CPI is one basket of goods, not necessarily the basket that everyone cares about. Besides, if interests are close to zero and assets are inflating as a direct consequence, there is an obvious arbitrage opportunity. Isn't that the point to focus on, rather than CPI?