This may be a complete shock to your system, but I'd like to introduce you to a concept called "upward economic mobility."
You see what happens around the world, particularly in developed countries, is that people tend to start off in menial minimum wage jobs and through various change events, like completing a degree, obtaining experience, or starting a business, move "upwards" into middle/high-wage jobs or enterprises.
This happens regardless of your status, so many refugees or low-skilled workers who obtained permanent residency - believe it or not - underwent change events to move upwards and make more out of their life. In Australia, you'd be an idiot if you didn't.
Hence, the once low-skilled pool of labor depletes and you need replacements via more people coming on working holiday or other visas. It's a cycle.
