I believe I am seeing the problem here.

You are, presumably unintentionally, using a blanket descriptor "mentally ill" and "drug addicted" to describe an extremely wide spectrum of expressions.

"Serious Mental Illness" definitionally requires substantial interference with or limiting of one or more major life activities (including maintaining a safe house, and maintaining employment).

You are conflating people's common use of the term "mental illness" - yes, we can agree that most people with say, seasonal depression, can hold down a job and maintain a house. This is not what San Francisco's visible homeless "mental illness" is referring to. They are suffering from Serious Mental Illness.

No, we cannot agree that most folks with Serious Mental Illness are able to muster the ability to sleep indoors, definitionally.

Again, "drug addiction." There is an appreciable difference between the character of the drug, and the addiction - aka "Chronic Substance Abuse."

That is, once again, I do not agree that someone with open meth sores on their face is going to hold down any sort of a job and/or be able to muster a safe home environment.

Next, you ask what has changed in the past few years? Then conclude only two things have changed in 10 years - "housing prices and rents."

While there may be a correlation, possibly even a causation, this is still an oversimplification of the problem. There are other cities, even in the US that have seen an increase in housing prices and not the corresponding inhumane treatment of both the housed, and unhoused in SF particularly.

I wonder if anything else has changed in SF in 10 years that makes it uniquely inhumane to the homeless, and also disproportionately affecting the entire character of the city? Could it be policies? Complete lawlessness and availability/encouragement/facilitation of new drugs and drug addiction?

There are at least two obvious problems that are unique to the West Coast, perhaps namely SF, 1) an overall increase in homelessness caused by certainly a multitude of factors that include much more than "rent," such as the bifurcation of particularly the SF labor market and the educational/cognitive barriers to "information technology work" versus the alternatives. That is to say, the problem isn't necessarily inherently that rents went up, the corollary is true that pay didn't go up for those experiencing homeless who were happily housed and paying rent before. Ought they move? Ought we relocate them? Ought we pay, say, fast food workers similar to MAMAA developers? It seems you suggest affordable government project housing? And 2) policy that makes it such that those who do suffer from Serious Mental Illness/Chronic Substance Abuse (by some counts, the majority of those experiencing homelessness) that does everything it possibly can to ensure they maximally suffer, while having the greatest possible negative impact to the bystanders, often other people experiencing homelessness, but also the housed, and business owners. That is to say, SF policies it as absolutely easy as possible to stay addicted, and as difficult as possible to overcome the addiction, while simultaneously pretending severe mental illness is not a thing (i.e. you [paraphrasing for emphasis] "most mentally ill people can maintain a house and a job".)

It seems our conceptualization "homelessness" is corrupted by inadequate, and inconsistent use of nomenclature.