Having mobilised cheap capital through interest-rate cuts after 2001, how and why did we allow banks and private equity houses to channel it into revaluing existing assets rather than creating new assets?
An interesting facet of this which I've seen discussed is the role which energy played in all this. You need energy to do things, and superficially, energy supply has been growing, though, oil supply, say has been on a bumpy plateau since about 2005. However, you also need to look at what you might call net energy. It takes energy to produce energy, so that the rest of the economy only has the energy minus that consumed by the energy sector to play with (technically, this is measured by the ratio: Energy Output/Energy Input, often referred to as EROEI - energy return on energy invested). If it takes 1 barrel of oil to produce one barrel of oil (so EROEI = 1), there is no energy left over for the rest of the economy. Back in the day, oil use to have EROEI of 100 - so lots of energy left over for your economy. But nowadays, new oil is often under an awful lot of water (deep sea) or is dirty rock (Canadian oil sands) and the EROEI is a lot less (e.g. 3 - 5 for the tar sands), which leaves a lot less for the rest of the economy.
In general, then, EROEI has been decreasing with time, which means that the energy for the rest of the economy is also decreasing with time. In other words it is increasingly harder (costs more) to grow the economy. It has therefore been suggested that one of the reasons for the move to trying to make money by shuffling bits of paper around which we've seen in the last few years is because of the lack of good opportunities in the real economy due to energy constraints.
It's quite hard to test this hypothesis;though the fact that there doesn't seem to have been any growth in e.g. the US economy for the last few years when you strip out the effect of all the excess borrowing; and Mervyn King's comment:
From the early 1990s to the start of the financial turmoil in 2007, total debt in the UKlink
relative to GDP almost doubled. Around two-thirds of the increase in total debt was
accounted for by lending to the financial sector. A marked expansion in debt of the
financial sector also occurred in the United States and the euro area.
The Bank did not stand idly by during this period. The Monetary Policy Committee set
Bank Rate to achieve the inflation target. Monetary policy – here and in our major
partners – was successful in controlling inflation and maintaining economic stability.
From the early 1990s until the onset of financial turmoil in 2007, output growth, both
here and in the industrialised world in general, was close to its long-run average.
suggest that something funny was happening. However, if this does provide an explanation of what's happening, it has important warnings for the future, since EROEI will only get worse,
Edit: Here's a picture of the EROEI cliff, to make things a bit clearer (thanks to the Oildrum and Euan Mearns):