Fewer workers. That's the whole point.
For years, companies have been investing billions into automation and efficiency improvements. Less and less humans are required to do the same work.
Of course, we aren't at 0 yet, but it's trending lower and lower. It doesn't take doubling a human workforce to double output anymore.
If you think of people working in the service sector, like fast food, or retail, I don't think most of them would cut it as a mason.
Aside from that anyone who has a way to make similar money another way would probably do so instead, I certainly would.
So my 20 second research shows the average salary for a plumber is around $50,000, with 90% making under $75,000. I bet more would be willing to be a plumber for the kind of money you mention, but that's not standard.