And mental illness; which is likely related

The biggest cause of homelessness is the cost of housing.

Sadly, no, it's drug addiction. 90% of the homeless in Seattle are drug addicted, alcoholic, or have mental health problems. About 10% are homeless for economic reasons.

So if I created a drug that cured drug addiction, corrected most psychological disorders (schizophrenia, bipolar, OCD, etc.), and raised IQ by 50 points (to get that "worthless" lower 50% up above the current average, that would be enough?

In fact I have created such a drug. Unfortunately at the moment I have neither the time to write down nor is this post sufficiently capacious to allow delineation of the significant factors involved in the development of the drug. However I do resolve to do so at a later time.

I have been offered billions to NOT release this drug or its derivatives b/c it's use would severely disrupt the USA wage structure: wages would plummet (as a tremendous number of highly-qualified amped-IQ former homeless entered the market), immigrants would suffer and indeed, everyone doing well would suffer. I have refrained from releasing the drug not for that reason but b/c, were I to do so, everyone who posts on HN would then hate me!8-)) But I digress...

My point is that, if we cured this problem(drug addiction) we would only be creating other problems. The only solutions that could work are socially unacceptable. Nonetheless I personally favor the "Golgafrinchan Ark Fleet Ship B" solution from "Hitchikers' Guide to the Galaxy":

https://hitchhikers.fandom.com/wiki/Golgafrinchan_Ark_Fleet_...

> if we cured this problem(drug addiction) we would only be creating other problems.

Like what problems, that they could then hold a job? Drug addicts can't hold a job. Their only interest/activity is drug seeking. This is why they are homeless.

I don't pretend to know how to cure drug addiction, but treating it as an economic problem is like giving cough drops to a lung cancer patient.

O ye of little imagination, how sad and frail thou appearest. Were only there a God to protect thee but I fear there is none and thou shalt die tangled on thine own snares.

Source? that's a pretty big claim.

And besides, this feels like a cause and effect issue. Are they addicted to drugs because they became homeless and it was the most humane way to cope outside of suicide? The alternative scenario where perfectly normal Seattle citizens get baked to the point where they can't keep a job seems fantastical.

Do you have a source for that? The numbers I’ve seen show about a third of homeless being drug addicted, and about a quarter with chronic mental health problems. I would assume there is quite a bit of overlap between those two groups.