The reason no one knew this woman's backstory (other than her family) is that no one knew her. She had no story that might show up on any ones radar. And with the raft of problems she had, I sure wouldn't want to spend any time with her. There's zip I could have done to help her. Way above my skill-pay grade. 

She walked away from help. Like so many street people, just wanting a free range life. These people die, on the same streets they live on.