While some claim market pricing is far-fetched, similar doubts were expressed about zero interest rate policy and quantitative easing as the 2007/2008 crisis broke. Yet both are still being used and 46 central banks have eased policy since the start of last year, nine of whom have rates below 1 percent.
The ECB and Bank of Japan have already adopted negative interest rates on bank deposits, and are expected to loosen policy further via a mix of deeper negative rates and more asset-buying QE.
If the central banks guarding two of the four main world reserve currencies are easing, the exchange rate impact will tend to strengthen the other two, dragging on exports limit any interest rate rises there.
Japan's prolonged fight to escape deflation is instructive. As the economy reeled from the collapse of the stock and housing markets, the Bank of Japan entered zero-interest rate territory in 1995 when it cut rates to a then record low of 0.5 percent.
More than two decades on, they've never been higher than that, despite near full employment and the largest debt burden in the world.
"Today's risks of embedded low inflation tilting towards deflation ... are at least as serious as the inflation problem of the 1970s. They too will require shifts in policy paradigms if they are to be resolved," Summers wrote last week.
For many, Japan shows that huge monetary stimulus from the central bank doesn't always lift inflation or inflation expectations, consumer or business demand, and ultimately overall growth - what's known as the "liquidity trap."
Joseph Gagnon, senior fellow at the Peterson Institute for International Economics in Washington and former Federal Reserve Board economist, warns against comparing every country to Japan.
Core inflation and employment in the United States are close to the Fed's targets, and even in Japan the latest round of QE looks finally be bearing fruit in consumer prices, Gagnon said.
Still, he says there was little for policy complacency.