What accounts for the shortfall in investment in the euro zone?

Euro-zone investment is abnormally weak, despite the low real interest rates, the recovery in corporate profitability, the rising public debt, etc. What accounts for the shortfall in investment in the euro zone? The significant decline in housing investment, but it can be estimated that it was too high before the subprime crisis; A trade-off that was negative for public investment when the fiscal deficit had to be reduced; The fact that companies did not increase gross investment to offset the increase in capital obsolescence (capital depreciation); this can be related to the increase in corporate debt at the time of the subprime crisis; The fact that the excess savings in Germany and the Netherlands no longer financed investments in the other euro-zone countries from early 2010.