We've been playing two games to mask insolvency: one is to pay the costs of rampant debt today by borrowing even more from future earnings, and the second is to create wealth out of thin air via asset bubbles.
The two games are connected: asset bubbles require leverage and credit. Prices for homes, stocks, bonds, bat guano futures, etc. can only be pushed to the stratosphere if buyers have access to credit and can borrow to buy more of the bubbling assets.
If credit dries up, asset bubbles pop: no expansion of debt, no asset bubble.
The problem with these games is the debt-asset bubbles don't actually expand the collateral (real-world productive value) supporting all the debt. Collateral can be a physical asset like a house, but it can also be the ability to earn money to service debt.
Credit card debt, student loan debt, corporate debt, sovereign debt–all these loans are backed not by physical assets but by the ability to service the debt: earnings or tax revenues.