They're correlated. The correlation is not 1, of course, but definitely positive. (Won't provide references -- there's plenty on the internet.) People in the bottom 30 percentile earn way less than people in the top 30.
Imagine you want to earn money and thus you need learn a skill. Which would earn you more money: learning to code or learning to stock shelves.
learning to code or learning to weld? Highly skilled work is highly paid work.