that it was worse than that, given that "real" activities suffered from under-investment during that period.

On the other hand, if we move back towards real activity (infrstructure and renewable energy come to mind, somehow), maybe the pain will not be so bad. The issue is about letting the wealth created be captured or not by the financial sector. If finance is brought down to size, maybe GDP will be lower, but overall activity may not be so much lower.

It's time for the real economy to default on the financial sector (rather than the other way round, as is happening now...)

In the long run, we're all dead. John Maynard Keynes