D.C. has missed a pretty big deadline.

By 2014, homelessness was supposed to be largely extinct in the nation’s capital, according to a detailed 10-year plan issued by then-Mayor Anthony A. Williams in 2004.

“This plan — ‘Homeless No More’ — can work. I know it can,” Williams said. “You can only finish the race if you begin.”

Well that didn’t happen. Instead, we have fallen into a deep crisis.

The number of homeless families in the city doubled in just one year’s time. Every night, there are more than 4,000 people sleeping in an abandoned hospital, on emergency cots in rec centers or in budget motels that city tax dollars pay for.

Things are so bad that even D.C. Mayor Vincent C. Gray’s own guy called it “catastrophic” at a D.C. Council committee hearing last week. “It sounds bad, and it’s worse than it sounds,” said Department of Human Services Director David Berns.

The thing is, it’s not that the 2004 plan failed. It’s that everything in the city has changed.

“When we were trying to implement this, the housing market was just firing up,” said Lynn French, who helped author that plan in 2004 and was known as the city’s homeless czar.

One of the solutions was to get more affordable housing lined up — at least 6,000 units were planned. The struggle back then was to get homeless folks — most of whom had mental health issues, drug addiction, were unemployed and were chronically in peril — stable and into housing.

But then, poof, “the housing disappeared.”

“Real estate became lucrative,” French said. And no matter how stable and employed those folks became, there were fewer and fewer places for them to go.

Developers came in waving wads of cash at folks who’d been living in the city for years. French remembers that they tried to give folks advice, telling them to make sure they have someplace to go before selling. But few listened. And as the bulldozers came and the cranes rose into the sky, the working class sold but then had nowhere to go.

Studies estimate that the city’s affordable housing stock has withered to half of what it was a decade ago. Meanwhile, family homelessness has doubled. See the correlation?

The face of homelessness in D.C. — and in many other regions — has changed.

“The majority of these families are working people,” said French, who left the city and now runs a boutique program called Hope and a Home that houses and supports — with a 90 percent success rate — 18 families a year.

It succeeds because the program has such a tiny group to work with. And counselors are on those families with budgets, financial planning and regular check-ins. They usually stick with the kids until college. The average stay with the program is about three years.

Great, but how do you manage that kind of care for 4,200 people?

There are few things more heartbreaking than a child who is in a shelter for Christmas or a parent sleeping on trains with a baby so she can be warm and safe.

And too often, the solutions focus on fixing them. How do we get this woman a better job? How can we get this family to financially plan? Why don’t they stop having kids?

Those are all good points. But the truth is, we have to start fixing the housing landscape as well as the people. Our region is becoming a Manhattan or San Francisco or Paris, even. It’s becoming a high-end playground that only the very privileged can afford to live in.

Take a look at what happened in Arlington when a nonprofit affordable housing developer announced an apartment building with 122 affordable units opening on Columbia Pike

“We had more than 3,000 people come and apply for those,” said Nina Janopaul, president and chief executive of Arlington Partnership for Affordable Housing, a nonprofit developer.

The changes in Arlington County have been dramatic between 2000 and 2012, when the area lost about 6,000 residents who earned between $50,00 and $75,000 a year but made a 250 percent jump — about 25,000 households — in those earning more than $200,000, according to the Center for Housing Policy.

“Where did all those people go?” Janopaul. “We think some of them are among the homeless.”

Why don’t they just move where it’s more affordable? Plenty of us would love to live in Paris, but we can’t. The apartments way out in Prince William County, however, are affordable.

“That’s a false savings,” Janopaul said. By the time those folks pay to commute into work and account for the added child care that usually comes with a long commute, it’s about as untenable as living in the District on minimum wage.

Local leaders simply have to get better at standing up to developers and demanding that a bigger share of their shiny, new buildings provide housing to a variety of income levels.

It was supposed to be One City, remember?

Twitter: @petulad

For previous columns, go to washingtonpost.com/dvorak.