First big wave of it (when you started to see tents appear under the highways and such) was 2008. Second big wave where that seemed to metastasize were Rahm Emmanuel's budget cuts. In particular, he shut down all the mental health clinics, and you ended up with a lot of people getting forced off their meds.
EDIT: Another thing, when I moved here there were still quite a few housing projects. I am not going to pretend they weren't rough. I walked through the ABLA homes most days and watched them get torn down. I had a kid hit me with a rock while biking through Cabrini. But there was a place where people could be off the streets back then. Now where do you go? What's waitlist for section 8 up to?
Section 8 has long wait lists. It seems kinda unbelievable to argue that destruction of thousands of units of low income housing didn't cause people to not have housing.
I don't doubt that many people are mentally ill. Before Rahm's cuts, we had a taxpayer-ran system of caring for the mentally ill.
(I've been a renter and a homeowner in Chicago; I grew up here).
To the extent that your premise is true (and I believe that, for many individuals, it is) that also speaks to our city pulling up the ladder on people. I was living in Logan Square when Rahm shut the mental health clinics down. There was one on Milwaukee. People protested for months. People on the streets obviously being in a very bad place and not getting help became a lot more noticeable after.
We’ve spent billions and billions on the “homes are the solution to homelessness” crowd. And the problem has only grown worse.
The agenda for during my adult life has been cutting services for needy (public housing, mental health, etc). Since we seem to agree that homelessness is getting worse isn't it also rational to agree that cutting these services is, at the very least, not helping.