Historically, the people doing "hard work" were peasants, serfs, and other lower-class people.
The people doing "skilled work" were the educated sons of nobility, and later of wealthy merchants.
An awful lot of the unhealthy and destructive dynamic in our modern work can be traced to feudalism.
Skilled, in late antiquity/mediaval times, meant the engineer doing trebuchet, or building ships, or building high quality steel, etc.. et.c.. it was actually hard work.
None of them were things that the ruling class/aristocracy did. They just paid for it (with the levies/taxes they took from their land).
Eventually another higher skilled level arised, as thinkers/scientists became hired by the court of a monarch, or baron.... and being a patron (paying for someone to do poetry, science, etc) was a sign of status.
The skilled workers have always been the middle class. It took the industrial revolution, where they could become rich themselves, and monarchy started becoming irrelevant.