An old East Asian proverb -- "visiting old, learn new" -- says that one can derive new understanding from learning the lessons of the past, and I think this is particularly apt with regard to the intellectual journey leading up to QQE. In practice, QQE has produced its intended effects. Inflation expectations climbed notably after the introduction of QQE.
This demonstrates that a strong determination by the central bank pushes up people's forward-looking inflation expectations. In addition, 7  the large-scale purchases of JGBs as part of QQE have exerted downward pressure on nominal interest rates across the entire yield curve.