I wonder if Paul Krugman has borrowed huge amounts of money and spent it already? If he hasn't done it, then why should we? If he doesn't trust his own theory for his own household, then why should we trust his theory for our country?
The answer is that of course he hasn't done that, because his theory requires that many people behave differently than each person. And yet when the many are made up of individuals, how can that be?
Krugman's theory has no legs. That dog don't hunt.