What caused Great Depression 2.0

According to The Economist that is.

1.Banks made risky, in some cases ridiculous loans and mortgages because the risky loans paid high interest rates.  When the risky loans defaulted, the banks were stuck.

2,  Regulators like the Federal Reserve failed to crack down on risky loans 'cause every one was making so much money doing it.

3.  Low interest rates, caused by a lot of thrifty savers in China 9 ( the savings glut) drove down world wide interest rates.  The Economist thinks this was a bad thing because investors looking for a better rate of return invested in "dodgy"  (clever British-ism that) securities.  In my view low interest rates are a good thing because it makes it easier for consumers to finance houses, cars, vacations, whatever, which is good for sales.  

4.  Banks and investors lost "trust" in one another.  They began to worry about "counterparties" (borrowers) defaulting, and so began to refuse to lend to the riskier of them.  Another way of stating this, is banks and investors finally wised up a little bit and began to evaluate the risk in what they were doing.

5. Letting Lehman Brothers go bankrupt.  This scared the bejesus out of  everybody in finance, causing them to stop lending.  " Non financial companies, unable to rely on being able to borrow to pay suppliers or workers, froze spending..."   This is pure imagination.  "Non financial companies"  (manufacturers for example)  never borrow to meet payroll.  They make payroll from sales revenue.  If sales dry up, they lay off workers.  They never borrow to pay suppliers, they just pay them late.  Ideally you can turn parts into product and sell the product within the 45 days you have to make good on a purchase order.  If it takes longer, the supplier gets paid later.  If sales dry up, you stop ordering parts.
  As far as I am concerned, they should have let some more companies go bankrupt.  Each bankruptcy teaches finance weenies that when they are not careful, they too can loose their jobs. 

6.  Letting the PIGs (Portugal, Italy, Greece) run up such huge current account debts, otherwise known as borrowing.   Nobody ( including the Economist) understood that joining the Euro means you can no longer print money to pay your debts.  Used to be a Greece could print a lot of money, the value of the money would fall, and so the amount of borrowing was automatically kept within sane limits.  Once they went on the Euro, they could no longer print their own money, and when the loans came due, they could not pay them.