A number of supply and demand factors, all characterised by a high degree of persistence, have been considered to justify this imbalance. Demographic developments, high demand for safe assets in emerging economies, increases in wealth and income inequality and a permanent decrease in total factor productivity are the main examples.
If we accept, instead, the view of those who suggest that we are in a transition towards the “second machine age”, low interest rates may be seen as the result of an adjustment temporarily characterised by weak demand and high unemployment; in the longer run, productivity gains due to the ongoing digital revolution and many other current and foreseen technological innovations will increase economic growth and raise real interest rates, even if with uncertain consequences for the distribution of incomes.