Thanks for this and the couple other comments in this thread. I get where you are coming from. First, I agree on the level that, let's say, "non-glamorous" work is important. So I didn't mean that the work of lifting bumpers to the station is stupid itself (it's necessary and someone has to do it) but that it's stupid for the welding specialists to do it.
But I am not sure the other axes you have to grind here. A surgeon and a janitor are both necessary to the functioning of a hospital, but obviously and not-controversially the surgeon is a lot less fungible. Like, in a pinch, you could ask patient's families to clean the toilet in the hospital room, but you wouldn't ask them to do the surgery.
And more obviously, if people were dying in the ER because the surgeons were busy cleaning the toilets, that would indeed be stupid.