The Seattle Times puts hard data to the trend all of us are feeling: the diminishment of Seattle’s middle class.

The numbers show that half of all new households in King County are poor, and the other half rich—giving truth to the old line about “how the other half lives.” Half of the new households are below the county’s median household income of $35K, half earn roughly double the median at $180K.

Those of us in the $35-125K range—there’s virtually no growth there. We’re mostly getting squeezed out of the Seattle sandwich.

This is a major shift in the city’s fundamental identity for the last century—a town largely made up of middle class folks. That fabric was once a major asset—there was relatively little urban poverty or blight, single family home ownership soared with the rise of affordable bungalow housing, labor strife subsided as business interests and unions settled on wage structures that lifted many in working class trades. Factory workers could own a home, maybe even a summer cabin, and put kids through college.

But that model has shifted. Not only is the middle class diminishing as a percentage of households in Seattle and King County, many in the middle class are being knocked downward. The trend is brutally apparent in Seattle’s African American community. Late last year, the Times reported that the median household income in the city had risen to over $70K, but for black families it was nosediving to $25,700. Compare that to black household income in the year 2000 which, when adjusted in current dollars, was worth over $44,000. Seattle now has the 9th lowest income for black households of the top 50 cities in America.

We’re also seeing a boom in homelessness at the same time we were supposed to be declaring victory in our 10-year plan to end it. This year’s one-night count showed 3,772 homeless—a 21 percent increase over last year. The Seattle-King County metro area has the fourth largest homeless population in the country, after the metro areas of New York, Los Angeles and Las Vegas.

There are many causes for this, and one is that the region’s prosperity attracts people who wind-up on the streets because they can’t find jobs that will pay them a living wage in a city that’s expensive to live in. Another is that—if history is a guide—we’ve seen homelessness increase not just during depressions and recessions, but also during times of high growth and prosperity in Gilded-Age style economies.

In the late 19th and early 20th centuries, Seattle saw a surge of growth and vast numbers of itinerant laborers flooded the city—more than could be accommodated. Homeless encampments, tide flat squats and flop houses proliferated. The city was faced with social service demands it had never had before. Vagrants were put to work to build roads in exchange for food, housing and tobacco, even while the city’s first millionaire fortunes were being built in the wake of the Alaska boom.

You won’t “end” homelessness if you have an economy that exacerbates inequality and strips hope from people getting onto safe, middle ground so they can set down roots, raise families, build community. You won’t have a healthy city, long-term, if you force out or force down the middle class. An economic ladder upward is useless and unstable without its middle rungs.