Everything we know about classic economic theory suggests the US economy should be experiencing Zimbabwe-like hyperinflation right now, thanks to the nearly $2.2 trillion the US Federal Reserve has pumped into the system.

But we’re not... yet.

Classic economic theory says that money supply can be used to stimulate the economy and our central bankers seem to agree. That’s why they’ve pumped more than $1 trillion dollars into the economy, engineered countless bailout bonanzas for zombie institutions, put Detroit on life support, and delivered a bunch of financial Band-Aids to the trauma ward -- all in a desperate bid to make Americans feel better about the global financial crisis.

To their way of thinking, the trillions of dollars have been a success. That’s why any meeting of the Group of Eight nations looks more like a mutual affection society with central bankers eager to claim credit and backslap each other in congratulations for having avoided the “Great Depression II.”

But by taking the Federal balance sheet to more than $2 trillion from $928 billion 2008, they’ve created a situation that should have resulted in an epic inflationary spike to accompany the 137% increase in liabilities.

Yet that hasn’t quite happened.

Core inflation -- which denotes consumer prices without food and energy costs -- has actually decreased from 2.5% in 2008 to 1.5% presently. And that has many investors who have heard the siren call of the doom, gloom, and boom crowd wondering if they’re worried about nothing.

So what gives?

Well, there are four reasons we haven’t yet seen hyperinflation:

1. Banks are hoarding cash.

Despite having received trillions of dollars in taxpayer-funded bailouts and lived through a litany of shotgun weddings designed to reinvigorate the shattered lending markets, most banks are actually hoarding cash.

So instead of lending money to consumers and businesses like they’re supposed to, banks have used taxpayer dollars to boost their reserves by nearly 20-fold, according to the Fed. The money the bailout was supposed to make available to the system is actually not passing “Go,” but rather getting stopped by the very institutions that are supposed to be lending it out.

Three-year average annualized loan growth rates were 9.6% before the crisis; now they are shrinking by 1.8%, according to Money magazine.

2. The United States exports inflation to China, which remains only too happy to continue to absorb it.

What this means is that low-priced products from China help keep prices down here. And this is critical to something that many in the “China-is-manipulating-their-currency” crowd fail to grasp. If China were to un-peg the yuan and let it rise by the 60% or more it’s supposedly undervalued by, we’d see a jump in prices here in everything from jeans to tennis shoes, toys, medical equipment, medicines, and anything else we import in bulk from China.

Chances are, the shift wouldn’t be dollar-for-dollar or even dollar-for-yuan, but there’s no doubt it would be significant.