The IMF’s “new mediocre” has the sound of a threat, but we may end by wishing it was a promise.

Not only has the IMF cut its world economic growth forecasts three times this year, but it is now warning of a sustained period of sub-par growth which looks similar to secular stagnation. This is the idea that the old norms of growth will not return of their own accord, held back by high debts and the after-effects of the 2007-09 financial crisis.

The global economy is “looking into the face of what we have called the risk of a new mediocre” period in economic growth,” IMF managing director Christine Lagarde said in Washington DC at the annual IMF and World Bank meetings. That points to a risk of “sustained global economic weakness over a five-year period,” according to the IMF, driven specifically by underinvestment and a self-perpetuating spiral of low confidence, low growth, inflation-undershoots, and yet more investment restraint.

The issue is that while the IMF has a clear idea of what we should do to blunt or avoid our mediocre shared future, its advice consists almost entirely of things we have already declined to do, or others which we have been busily implementing to unsatisfactory effect.

These reactions can briefly be divided into old bromides which we will not agree to follow and more of the same monetary policy which helped bring us to where we are now. Is there a new prescription? The IMF’s advice relies heavily on what it calls growth-friendly policies on the fiscal side, a heavy dose of labour market reform, and infrastructure investment, particularly in the US and Germany, with the presumption being that much of it will be debt financed by friendly financial markets.

None of this is new, and though you could argue that the importance of reform and infrastructure investment is greater in a low growth world, one in which every tenth of a per cent of growth is a greater part of the whole and therefore more valuable, you have to ask why we have not done these reforms so far.

The reasons are political, or if you like cultural. At a discussion at the IMF/World Bank meetings last Thursday, former US Treasury Secretary Larry Summers described a Japan-like trajectory for Europe: “That is the path Europe is on without a substantial discontinuity of policy. What’s happening in Europe is not working.”

Summers noted that Europe has consistently delivered lower than expected growth and inflation in the years since the crisis, arguing for debt-financed spending on infrastructure, and not just those things which produce streams of revenue. But German Finance Minister Wolfgang Schaeuble did not sound like a man about to reach into the pocket of the German people to fund pothole maintenance and bridge building.

“We must solve the problem of today without falling back to the mistakes of the past few years,” Schaeuble said in response to Summers, having earlier in the day remarked that “writing checks” was no way for the euro zone to boost growth.

Infrastructure is perhaps a good idea, but one of many which will find only stony soil in the current environment, particularly in Europe and the US. There just seems little likelihood that the G20 will actually produce much by way of new committed infrastructure spending.

That brings us to monetary policy, that most popular prescription, not least because it is one in which the money can be created by fiat by a few people around a table rather than via a messy and painful political process. The IMF is clear that it expects the European Central Bank and Bank of Japan to provide more stimulus, and warns as well of the risk that a Federal Reserve tightening may affect the rest of its lukewarm forecast.

While it is impossible to argue that central bankers should sit on their hands while the world suffers through a period of sub-par growth, it is also difficult to muster much enthusiasm for a set of policies which, while perhaps blunting the effects of the malaise, have manifestly not ended it.

Sometimes the best prediction of where things will be is simply to look at where they are now. Translating that in economic terms means we are looking at a continuation of the failure to follow structural recommendations such as infrastructure investment, while relying on monetary policy as the more easily implemented policy.

Monetary policy has undoubtedly had great impact in financial markets, but even though it is now looking like we will get more easing, or less tightening, those in the markets in the past week or two have been far less reassured. Let’s hope that particular drug is not having a progressively diminishing effect.