We had one in town when I was a student. The thing had a name. It was called Schweinebunker.
For 1900 $/mo, you can get a bedroom in a really nice 2 or 3BR place in the desirable neighborhoods or a studio/1BR in the undesirable neighborhoods (sunset/richmond). I don't understand why the people in that article are living like that (Poor credit? Desperation to find a place fast? Ignorance of the existence of Craigslist?), but they're very, very far from being representative of SF real estate.
A purchasing power metric (that includes cost of housing) would indicate that.