It is a more difficult job to fill than an office job.
When I had physical jobs in my youth, I'd come home exhausted. My father told me to get a good 8 hours of sleep, and I would be fine for the next day. When I moved into a career where I used my mind (Engineering and Design) my father also taught me that I needed a different type of a break to rest my mind. It took me decades to recognize his advice. Two different types of muscles. Two different kinds of rest.
Both equal, and important lines of work.