You can't even go to rest rooms, without leaving laptop bags in cars. That's what California has become these days. Not just San Francisco, every city in California is like that.
I could list fifty highly positive experiences but the current narrative seems to focus on being negative.
I like the quote from Paul Kantner (of Jefferson Airplane): "San Francisco is 49 square miles surrounded by reality."
You can totally leave your bag in the car and it'll most likely be fine in Santa Barbara, Pleasanton, Livermore, Truckee, ... (outside tourist areas).
As others said, it's about social cohesion of which there is little, especially in large cities but more and more small towns as well.