Figuring that one's labor is required then the arbitrary metric of "skill" doesn't apply. A rhetorical question explaining this is "Who is deserves more money, A doctor or the farmer that feeds him?" Since the farmer's labor is needed for the doctor to survive and have enough energy to actually provide medical care, then they are of equal value and deserve equal compensation, no matter how "skilled" the doctor is.
Absolutely correct. I'm everyone got a college degree, would we still go out to eat? Would the garbage need to be collected? Would you still need someone to fix your car? The amount of money a person gets determines the quality of life they are allowed to enjoy, so the argument really is about "how much luxury does the working class deserve" and my answer is "enough that they don't have to worry".