Like most of those meat in the sandwich management jobs it either needs some form of formal qualifications, management experience or time in trade or some mix of all. Depends on the contract and needs.
That being said you could have been paid $700+ per day as a trade building the desal plant in Victoria due to a lot of government incompetence. And even in the airlines a line pilot at some airlines could be making more than a checkie working days off and extensions. But those are exceptions not the norm. I know a few captains on a SAAB who grossed over $200k for the year during 'pilot shortages'.
Supervision just requires a firm hand with trades: no pay until the job is right. And it doesn’t take long to learn what is correct and what is not. And picking up tools to expedite the job isn’t the way to ensure the contracted trades meet their contracted obligations.
There's not a lot of people who can do this well, in the US it's probably easier to find ex military NCOs and the like that are suited, but the pay is high in Australia for a reason. No company is going to hire you on $100k+ a year without some talent/experience background and then stay hired as well you have to work for that cash.
I'd also say good luck to make trades work for free until the jobs completed on a large worksite that they could be working several months on, I think fairwork might be paying a visit before that. Again not talking about building private houses here.