This is because the richer countries need to rely primarily on "smart growth", that is, increasing total factor productivity through innovation and technological change, while the poorer ones can grow robustly for long periods merely by imitating more advanced countries and adding more inputs of labor and capital.
Europeans have decided to share a common destiny – based on profound friendship, peace and prosperity – which has guided European integration for the past 60 years. We at the ECB are proud to be responsible for delivering price stability to our 330 million fellow citizens in the euro area and to contribute to the prosperity of the European Union as a whole.