The reality is, for this kind of work, none that are able to be ridden by bike with your tools. Australia is a massively spread out country, with many builders driving anywhere from 15 to 60 km each way to their jobs each day.
Combine that with multiple jobs in the one day, and it’s completely impractical to consider riding.
There may be the odd handyman who works only in their own area, and that would work.
But, by and large it’s the reality of Australian building.
Weird. My wife is Australian and I’ve visited many times. Even places as small as somewhere like Broome have electricians and plumbers who work primarily in Broome - and that’s before you go to places like Adelaide, Darwin, Perth etc etc
Our plumber is about 25 km from our house. Our sparky is about 15.
That’s a long way to ride your gear back and forward. Imagine the downtime on any given day to riding. These people are charging out at anywhere from $150 to $300 p/h. They’re not going to lose that income riding those distances.