Strawman.
Unskilled /= low pay.
High supply of workers/candidates vs. demand is what makes the pay low.
There are plenty unskilled jobs that are relatively well paid because, for whatever reason, not enough people want to do them.
Painter/Decorator for example, how hard is it to paint a wall.
"Hard" as in technical difficulty, effort required, or safety risk? The first is the only qualification of "skilled labor." However, all of these factors can affect pay.