Social housing does work but can be hard to do well.
Places in London that built large scale apartment complexes for social housing saw them turned into slums with rampant drug use, violence and criminal activity.
And it can be harder to get smaller-medium density housing to work because you're constantly fighting against local governments and NIMBY types.
Slums are a substantial step up from people sleeping on the street. It localizes the issues, such that social services can be provided centrally, it keeps the more problematic elements away from the rest of society, and at the end of the day having an address and shelter is a huge step up from having neither.
If building slums eliminates homelessness, that's a net win. No need to let "perfect" get in the way of "better".
>Places in London that built large scale apartment complexes for social housing saw them turned into slums with rampant drug use, violence and criminal activity.
...some places were just badly designed and encouraged the slum aspect (and associated problems).
Homelessness is not a complex problem to substantially ameliorate: https://seliger.com/2022/06/29/homelessness-is-a-housing-pro.... Northern California has tried absolutely everything to reduce homelessness except building more housing: https://www.mcsweeneys.net/articles/i-will-do-anything-to-en....