Complacent regulatory and fiscal policy design meant that the entire euro area became increasingly vulnerable to a turn in sentiment that would make the servicing of vastly increased debt ratios problematic. Some countries with high public debt at the start of EMU did not bring their debt ratios down: with the newly lowered interest rates, the situation looked manageable.
Incidentally, if you look back at 1992, the White Paper on the National Life Style published by the government that year was titled, “The Advent of Society with Low Birth Rates: Its Effect and Response.” With hindsight, Japan around that time was painfully looking for ways to recover in the aftermath of the bubble economy.