This article makes a number of statements which run counter to empirical research I've seen on this topic, and doesn't cite anything to support these claims. My understanding is that the majority of CA homeless are in fact from CA, and few people are "professional vagrants". Some Ezra Klein episode I listened to last week brought up a number of highly detailed surveys from which I'm drawing these conclusions.
I see lots of statements like "many homeless prefer to live on the streets where they can freely use drugs", particularly in right-leaning media, but IMO these are kind of strawmen that elide a lot of the significant elements of the situation. Drug addicts don't just "prefer" to stay where they can use drugs, it is for all intents and purposes a biological necessity. Shelters which will stop people from using ex. opiates are going to be non-starters unless they an offer viable paths out of addiction, or embrace a harm reduction approach which gets pilloried left and right in the US.
The overall framing that "social services incentivize homelessness" also seems to run up against the fact that the largest driver of homelessness is obviously the rising price of housing. Presumably if social services (which in this article seems synonymous with money spent on shelters) were the cause of SF's homelessness problem you would see people using the shelters they moved there for. But as the article points out this isn't the case; engagement with the expensive services is far below the desired levels. If people simply wanted to live somewhere they don't have to pay rent and can use drugs freely there are a number of extremely accommodating rural areas for this lifestyle. It seems more likely to me that SFs housing market pushed a large number of people into penury, and some of them are coping with their extreme deprivation by using drugs. Not that SF has somehow become a national destination for homeless (who exist everywhere in the country, and every city seems to think that they are somehow a magnet for them).
I am sympathetic to people who prefer not to have encampments in the public space, but I think we need to be clear-eyed about the causes and potential solutions. Simply "cracking down" with aggressively enforced urban camping bans hasn't worked in pretty much any city its been tried in (see Denver, where the cops have spent the better part of two years pushing the city's 4K homeless from block to block, with overall levels only increasing). Presumably it would be better to (a) stop the flow of people into homelessness with a stronger social safety net and a better housing supply and (b) increase the flow out of homelessness with better rehabilitation programs.