Are the glory days finally over for Boston’s Financial District?

OK, maybe it’s too early to write off what amounts to the economic headquarters of New England, with the blocks between Summer and State streets home to the largest collection of office towers north of New York.

But there are some clear warning signs that the once-vibrant heart of the region’s economy is experiencing a hardening of the arteries.

The Financial District’s office vacancy rate is a hefty 20 percent, double that of the Back Bay. And the district’s towers are aging fast, with only three major new high-rises built in the last 20 years.

From law firms to venture capitalists, corporate Boston is voting with its feet – and heading to the Back Bay or to some shiny new suburban office palace perched along Route 128.

Without some bold and creative strokes by business and civic leaders, Boston’s all-mighty center of finance and industry could be headed into a long and painful decline, if it isn’t already there.

But the tricky part is what’s to be done – for that, as they say, is the billion dollar question.

“It’s an interesting thing,” noted William McCall, president and principal of brokerage McCall & Almy and an elder statesman of the downtown Boston market. His firm’s offices are just off the Post Office Square park. “For 95 percent of my career I have always recommended the Financial District. Today I have to tell you the Back Bay is the place to be.”

Look at the numbers and trouble is easy to spot. Last year was hardly an easy one for the commercial real estate business, but the Greater Boston office market actually posted some gains after a couple years of brutal reverses.

That is, just about everywhere except for the Financial District.

Stalled Momentum

Firms and companies of all types began to fill in empty office space in the Back Bay and along Route 128 alike, with Back Bay’s vacancy rate falling to a svelte 10 percent.

But the Financial District actually saw the amount of vacant corporate suites grow by another 216,000 square feet, helping keep empty space above the troublesome 20 percent mark, according to Jones Lang LaSalle.

Dig deeper and there’s still more trouble to behold.

In the 1970s and into the 1980s, an explosion of building downtown made Boston’s glimmering skyline a symbol of the Hub’s renaissance after decades of lethargy.

But the last two decades have been a different story, with just five towers getting built – and that includes 125 High Street and Don Chiofaro’s Two International Place, which both began construction in the late 1980s.

In fact, much was proposed but never built, including a plan to put a skyscraper atop South Station and “Tommy’s Tower,” Mayor Thomas Menino’s star-crossed effort to crown the Hub’s skyline with a billion-dollar-plus, 1,000-foot-tall skyscraper.

And it could be years before we see plans for another office tower take shape downtown, if at all.

So what’s driving the malaise?

A whole bunch of things, but the key has been a shift in the way companies do business.

Downtown Boston’s sky-rises were built not just to accommodate a highly paid, elite executive corps, but also small armies of clerks, typists, draftsmen and others we now call back office workers.

Many of those run-of-the-mill office jobs have been shipped to India, or cheap space in the suburbs, leaving huge vacancies in the lower floors of towers across the Financial District.

Those jobs are gone – and they aren’t coming back.

With less foot traffic, the amenities the downtown business district had to offer have also withered. It’s hard to imagine now, but battered Downtown Crossing was once a destination for the Financial District lunchtime crowd.

Next Time The First Time

By contrast, the Back Bay has all the amenities you could want and then some, from hotels, restaurants and shops to condos, apartments and parks.

One approach, taken by City Hall’s development arm, has been to try and bring a little of the Back Bay to the Financial District, encouraging new restaurants, shops and housing.

That’s been a hard slog, with housing market woes having put a damper on some of those efforts. There’s also a campaign to revive Downtown Crossing, though given the near hopeless state of the half-demolished Filene’s site, this could take years to bear fruit.

But maybe it’s time to throw out the playbook and look at the Financial District in an entirely new light.

It’s just possible that the Financial District’s glory days are gone for good, and, if that’s the case, no amount of urban planning or fancy new strategic plans out of the Boston Redevelopment Authority will bring them back.

David Richardson, executive vice president and principal at McCall & Almy, knows what the next chapter could look like.

Some cutting edge New Economy or life sciences firm makes a bold move downtown, carving out a beachhead for a new sector.

Or maybe the knight in white armor is a blue chip financial firm, which decides Boston is the place to be and opts to buy up a chunk of downtown and build a skyscraper, he muses.

But how to make that happen is another question entirely.

“It’s frustrating,” Richardson acknowledged. “I have been doing this for 30 years. The next time I hear someone say ‘I want to move my corporate headquarters to Boston’ will be the first time.”