I would assume SamA knows this. "Worthless" jobs are typically jobs that are actually valueless, but we continue to irresponsibly support their existence. My favorite example is break bulk shippers before the widespread adoption of containerization. Unions negotiated deals where workers would basically just stand around and get paid regardless of the complete lack of need.

The jobs you mention could eventually get to the point where they are actually worthless, ie: robot fast food workers, but I don't think anyone is arguing we're there yet.