The real question is: The country as a whole did not lose any wealth in the financial crisis, but why many people are getting poorer and the real tangible and consumable products are getting less produced?
No, wealth was not destroyed during the crisis. It is is during the boom that wealth is destroyed.
When you build a house that no one is going to value enough to live in you are destroying wealth. So it is the distorted market signals during the booms that make people allocated wealth to wastefull use that is the destruction. The crisis is just the correction when people start to realise they destroyed capital...