I know two site supervisors personally and they are both on 150k + car + phone. One has no trade qualifications but has being doing supervision for about six years, the other has foreign chippie quals and has been supervising for two years.
A dear friend pays $500/day for smart self-starters helping him build sheds after approx 12 months.
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.