The reason that it will NOT all spring back as after other recessions is the high liklihood that what we are now facing is a Depression. One that, given the 21st, will out gun the 1930s by some margin.
Of course, this is only a possibility but those who have looked at history and looked at the financial state of the world across the last ten years, consider a Depression will arrive at some point. If not now, then in the future.
The reasons that I think it will be now are many but can be illustrated by the fact that, after the 2008 problem, no substantive changes were made to the financial system. The Banks promised their friends in Govt that it would all be fine and Govts printed money. Again.
Soverign Debt is now HUGE, not just corporate debt.