When the co-manager of the world's largest bond fund talks, even central bankers listen.

That's why Mohamed El-Erian, chief executive of Pacific Investment Management, drew a capacity crowd of more than 200 for a lecture Wednesday at the Federal Reserve Bank of St. Louis. His firm, known as Pimco, manages $1.4 trillion of assets and has been a huge beneficiary of the Fed's creative policymaking.

So, what does El-Erian think the U.S. central bank, and its counterparts in other countries, can do next to get the world economy out of its rut?

Unfortunately, not much.

El-Erian gives the Fed, the European Central Bank and others full credit for having prevented a global depression in 2008-09. He also agrees that creative monetary policy making has propped up asset values around the world – including in the bond markets where Pimco makes its livelihood.

That success, however, hasn't carried over to the things most citizens care about, like job creation or income growth or housing values. Going forward, El-Erian says, monetary policy may have even less leverage.

“We have tested like never before the very concept of central banking,” he told his St. Louis audience. “My sense is that the balance of benefits, costs and risk has shifted and we’re getting nearer to the point where central bankers ... go from being net effective, to being net ineffective.”

If the Fed can't do much, who can? El-Erian says we should view the central banks' actions as buying time for other policymakers, including Congress, U.S. housing regulators and European governments.

All of them have been slow to address the overhang of public and private debt that's choking off economic growth.

“Think of a very dark cloud outside your door,” El-Erian said. “If you're not sure how that cloud is going to evolve, you’re not going to go outside.”

“It’s time for other policymakers to step up to the plate and join central bankers in pursuing the goal of safe deleveraging,” he pleaded.

Right now, that looks like a tall order. European countries need to shore up their banks while reducing budget deficits. Congress faces a Dec. 31 deadline to figure out how to handle expiring tax cuts without ballooning the already unsustainable long-term deficit.

El-Erian sees a slow-growth “muddle through scenario” as the most likely future for the U.S.

Chris Varvares, president of Macroeconomic Advisers in Clayton, thinks El-Erian has a good read on the policy situation, but may be a little too pessimistic.

“I think his characterization of where we are is correct,” Varvares said after hearing the speech, “but his notion of muddle through is probably down toward 2 percent growth” in gross domestic product. Macroeconomic Advisers is forecasting 2.6 percent GDP growth this year.

Those numbers may not very far apart, but Varvares says it's the difference between a job market that's stuck in neutral and one that improves a little each month. In the early months of 2012, we've already seen signs of progress on the job-creation front.

One doesn't have to share El-Erian's pessimism, though, to share his concerns. The Fed's and ECB's injections of liquidity have worsened inequality, he says, and led to an emphasis on short-term trading, as opposed to long-term investment, in financial markets.

In short, central bankers have kept things from getting worse, but they alone can't make things better. The storm clouds won't lift until the world's political leaders contribute some bold policy moves of their own.

Read more from David Nicklaus, who is the business columnist for the Post-Dispatch. On Twitter, follow him @dnickbiz and the Business section @postdispatchbiz.

David Nicklaus is a business columnist for the St. Louis Post-Dispatch.