I think the most obvious explanation is that 1) lots of stores are closed and boarded up, and 2) Since we don't pursue property crimes under a thousand dollars and often more than that, people don't bother calling the police, so their experience of crime begins to differ from the crime stats. Those are the cases of people walking into Walgreens, grabbing stuff, and walking out. A crime was still committed, but no one called the police since they know they wouldn't do anything, so it doesn't show up in the crime stats. Lots of people don't bother calling the police for things like car breakins for the same reason. If there's no benefit to you and it takes time, then why do it?

One interesting way to test this is to look at NCVS (surveys of random people asking if they were the victims of crime) versus crime stats as reported by police departments. In about 2 years the 2020 data will be out, and then we can see whether the push in places like SF to decriminalize property crime resulted in an increase or decrease in property crimes in the victimization survey, but you can't really judge reported crime stats by police departments when they are under a do not pursue mandate. This would give us a more rigorous approach than looking at a sample of nextdoor posts.