Simon Wren-Lewis, professor at Oxford University and a Fellow of Merton College, says the ECB failed to undertake quantitative easing at the appropriate time because of mis-diagnosis of the problem:
The story told by many is that the Eurozone crisis is a result of fiscal profligacy in some countries, and the need to put that right quickly because of market pressure. This account misses two essential underlying causes of the crisis, which have to be recognised if a solution is to be found. The first missing element ….. private sector demand was too strong, encouraged by large capital inflows from abroad and real estate bubbles…..The second key feature of the current crisis is also a result of excess private sector demand in periphery countries, and that is a banking crisis.
……There is an underlying pattern behind Eurozone policy errors. They reflect a view that macroeconomic difficulties are primary due to bad government decisions, while private sector decisions within a free market environment do not create problems. Whatever label we want to give this view (Ordoliberal or Anti-Keynesian), it is the fundamental cause of the current Eurozone crisis. Its persistence despite all the contrary evidence allows the crisis to continue and threatens the integrity of the Eurozone itself.

Colin Twiggs is a former investment banker with almost 40 years of experience in financial markets. He founded PVT Capital (AFSL number 546090), which provides income and growth strategies to wholesale clients.
Colin also co-founded Incredible Charts and writes the popular Patient Investor newsletter.
Using a top-down approach, Colin identifies macro trends in the global economy and then combines fundamental and technical analysis to evaluate opportunities in sectors that stand to benefit.
Focusing on interest rates and financial market liquidity as primary drivers of the economic cycle, he warned of the 2008/2009 and 2020 bear markets well ahead of actual events.

Correct analysis of the cause. And to see the correct policy to manage the consequences, read “The Holy Grail of Macroeconomics” by Richard Koo, Wiley, 2009