What do you mean that immediately after the housing collapse people realized that there was a far larger debt bubble? Its a good thing we've spent the last 15 years reducing the bubble and preparing for the risk of it.... oh wait Im now being told we did none of that. Uh huh... we increased our debt... mm hm and further increased the bubble both for financial institutions and for the general populace via credit card debt.... glass-steagall would have really helped keep things in check.... no new safety net in place....

Huh so it turns out that we have a far larger, multi industry sweeping debt bubble both for individuals and for banks as banks lend out 10x their value to people and companies that operate on razors edge thin margins when it comes to risk absorption/adaptability. Add into that massive shorting from major institutions that if their valuations shift could result in significant margin calls leading to a cycle of loss.

Cycle of loss being that a heavily leveraged and shorting company would be forced to pull/sell their investments (bonds/stocks) to hold more liquidity/cash. Doing so usually results in a loss, especially with a declining market, thus resulting in lower than expected revaluations. The revaluations lead to the company being margin called as their collateral value declines, which would force them to close their shorts, which in turn would reduce their cash/liquidity, and the process repeats.

Soooo yeah turns out the government giving the banks a blank cheque by bailing them out in 2008 may have resulted in an far broader reaching economic collapse.