Even if it’s true that most unhoused people are mentally ill — and I agree with Tim’s reply — you have must consider causation versus correlation. Is an unhoused person dysfunctional because they were always that way and thus doomed to lose shelter, or are they dysfunctional because living on the streets is extremely damaging?

You see this question a lot when discussing drug usage among homeless. The percentages of addicts is undeniably high; we know this from point in time counts, for example. Some people take that as proof that homelessness is the fault of the homeless: they made the bad decision to take drugs, and that’s why they lost their jobs. But there’s also a lot of data showing that people are more likely to become addicted as a way to cope with street life.

And if, in fact, losing your home is something that can happen relatively easily in part because of wealth inequality, we’re right back to the original assertion.

Underbuilding is for sure another factor. It’s just not the only one.

I hear a lot of accounts of relatively-normal people who talk about one member of their family who is homeless and living on the streets because they stopped letting that family member live with them because they did things like violently attack children in their home, or steal money in order to buy drugs. So this makes me think that a lot of visibly homeless people were in fact dysfunctional before they became homeless.

And this is relevant for any institution at all that tries to house such people, including the state. If the state provides some kind of basic housing with electricity, what happens when the people living there rip wires out of the wall so they can sell the scrap for drug money (a major reason why most landlords don't want to rent to really poor people)? Will someone prevent them from doing that (i.e. institutionalization), or will the state itself evict that person from their housing and allow them to live as a homeless street person?