When someone is given the Nobel for achievements in one are of economics that doesn't instantly make them experts in other areas of economics.
As one other Nobelist puts it, the current problems require a new understanding of the points Adam Smith made.
And the current problems are also laying bare quite how little we know about macroeconomics (as opposed to micro....)
For example, the Goldilocks Theory of Macroeconomic Stimulus.
One way of putting it, we don't have a British banking crisis, we have a Scottish banking crisis. A new Darien perhaps?
Don't try to trim government spending, slash it by simply stopping government from even attempting certain things.
And finally, OK, economists don't know everything about the economy but then that's not uncommon, for a science not to know all the answers.