Because people have different capacities. People with the capacity for what we consider "skilled" positions can be directed towards technology based positions.

Because people have different capacities. People with the capacity for what we consider "skilled" positions can be directed towards technology based positions. But there are people out there who, no matter how hard they try, lack the mental capacity to do what we consider skilled labor. I don't say this as an insult. I went to school with a guy who is still one of my best friends and he's just one of these people. He worked as hard as he could, studied for hours, and he still only got Cs in school. He doesn't have the capacity for that kind of thought. So when robotics gets to the point where it can do his job as a laborer on the docks he won't be able to be repositioned in the same way people with the capacity to take IT positions have been in the past