Dragonlady
Designing Woman
Sure they do. How do you think they got there?
They got there because they had no other choices. Many have emotional problems or mental illness. In the USA, military veterans have a very high level of homelessness compared to citizens in general. When you see a lot of homelessness in certain classes or types of people, it's never because they made choices, it's because they have no other choice.
Poverty, mental illness, drug abuse, survivors of physical and sexual abuse, lack of affordable housing - all are contributing factors to homelessness.