Robert Skidelsky pravi, da je za padajoče stopnje rasti BDP v razvitih državah kriv izpad zasebnih investicij zaradi padajoče stopnje dobičkonosnosti. Posledica tega je sekularna stagnacija. Po njegovem bi izpad zasebnih investicij morala nadomestiti država z naložbami v infrastrukturo in subvencioniranjem zasebnih naložb.
The generalized version of this proposition is that secular stagnation – the persistent underuse of potential resources – is the fate of all economies that rely on private investment to fill the gap between income and consumption. As capital becomes more abundant, the expected return on new investment, allowing for risk, falls toward zero.
But this does not mean that all investment should come to an end. If the risk can be eliminated, the investment engine can be kept going, at least temporarily.
This is where public investment comes in. Certain classes of investment may not earn the risk-adjusted returns that private investors demand. But, provided that the returns are positive, such investments are still worth making. Given near-zero interest rates and idle workers, it is time for the state to undertake the rebuilding of infrastructure.
Those who know their history will recognize that Summers is reviving an argument advanced by the American economist Alvin Hansen in 1938. Owing to a slowdown in population growth, and thus lower “demand for capital,” the world, Hansen claimed, faced a problem of “secular, or structural, unemployment…in the decades before us.”
The prolonged boom that followed World War II falsified Hansen’s projection. But his argument was not foolish; it was the assumptions underlying it that turned out to be wrong. Hansen did not anticipate the war’s huge capital-consuming effect, and that of many smaller wars, plus the long Cold War, in keeping capital scarce. In the United States, military spending averaged 10% of GDP in the 1950’s and 1960’s.
Population growth was boosted by a war-induced baby boom and mass immigration into the US and Western Europe. New export markets and private investment opportunities opened up in developing countries. Most Western governments pursued large-scale civilian investment programs: think of the US interstate highway system built under President Dwight D. Eisenhower in the 1950’s.
This mixture of stimulating events and policies enabled Western economies to maintain high investment ratios in the post-WWII years. But it is possible to argue that all of this merely postponed the day when the expected rate of return to capital would fall below the minimum rate of interest acceptable to savers, which would happen as capital became more abundant relative to population.
Robert Skidelsky, Project Syndicate