Regarding
>>> I don't buy the line that Bear was brought down by shorting. Rumours and a run on the bank maybe, but shorting no. If shoritng can bring an entity down, then it is already dead.
Of course, people are entitled to their views.
Entities like BSC and LEH (and most others) function in terms of many parameters. Their existence depends on those parameters satisfying certain constraints just as the value of your house depends on parameters and how they relate to certain constraints.
In principle, all your neighbours up and down the street could sell their houses to one another for a tenth of their value, if their intent is to temporarily depress the value of your house. This is much easier to do for our "neighbours who operate in the markets."
It is very easy to destroy companies via systematic shorting, and many entities have suffered such a destruction. All shorting needs to do is to bring one parameter (e.g., price) to a point where crucial constraints are violated. At that point animal spirits take over and outcomes are more or less predictable.
Prior to these points (perhaps aptly called "threshold points") it is possible to ward off such a crisis. But one has to acknowledge the existence of such a point first, or dwell in ostrich-land. FNM and FRE are at such points now.
At the heart of things there is great simplicity --- animal spirits, greed, fear and related actions. The complexity lies in size, volume and information/misinformation. This is the noise.