Try to imagine you're one of the people sitting on the fringes of the workforce. You're not a particularly bright person, who will never get a job in an office, moving from job to job, short 1-3 month labouring contracts that don't pay much, then in between those periods there is some unemployment. But every time you go to Centrelink you're faced with ridiculous hoops to jump through, they don't help you get a job, they just make it harder to collect the welfare between jobs. You pick up the newspapers and turn on the news, and everywhere around you there are voices telling you what a piece of shit you are for being on Newstart.
Some people are going to battle through this and position themselves well, despite challenges. Plenty of people are not. There are none of the benefits of unionised labour for these people - getting a union job is a far off dream.