Some people still think homelessness is a housing problem

In order to provide work for architects, this fellow writes at an architectural forum: "I would suggest that the AIA Housing KC develop a National Housing Policy that says, in effect, that it should be a right for every citizen in the United States to go to bed each night in a safe, secure and weather tight environment. In other words, we need to eliminate homelessness from our nation's vocabulary."

Substance abuse is often a cause of homelessness. Addictive disorders disrupt relationships with family and friends and often cause people to lose their jobs. For people who are already struggling to pay their bills, the onset or exacerbation of an addiction may cause them to lose their housing. A 2008 survey by the United States Conference of Mayors asked 25 cities for their top three causes of homelessness. Substance abuse was the single largest cause of homelessness for single adults (reported by 68% of cities). Substance abuse was also mentioned by 12% of cities as one of the top three causes of homelessness for families. According to Didenko and Pankratz (2007), two-thirds of homeless people report that drugs and/or alcohol were a major reason for their becoming homeless.
In many ["some" would be a better word choice, nb] situations, however, substance abuse is a result of homelessness rather than a cause. Link

Further more, a tiny percentage of the homeless are chronically homeless.

5% of the nearly 2 million homeless people reported by the USHUD in 2009 categorized as chronically homeless, nearly all people living without a home for more than a month have family problems and some kind of disability, including drug or alcohol addiction or mental illness. Based on the 2009 HUD Homeless Assessment Report to Congress, Link

So unless the architects have found some sort of super-human solution to drug and alcohol addiction, mental illness and chronic family problems, they need to look elsewhere for a solution to their own employment problems.