Australians or anyone who knows!

In Australia we have a thing called centerlink which is a government run thing that helps people out by giving them money. Now as long as you aren't super rich or a kid living with parents who are rich. You can get it. Almost anyone can. 
Now in Australia like everywhere else in the world we have people who are homeless and it's sad. And while I know even with getting money and having a job you can still struggle, I know because that's been my life. 
I also get you can be between homes and all that. But when someone is completely homeless in Australia and is for a long time. I don't get it. Almost anyone can get centerlink and go to a place that sets you up for interviews for FREE for jobs. 
Obviously I don't know everyone's story and I can't always assume. But why wouldn't some even try and stay homeless? And beg for money on the streets when we are lucky to live in a Country that provides so much for us and for those who need it. 
Can anyone explain this to me?