Not the parent commenter but I think they’re suggesting that the degree may not be the cause of the increase in earnings, but rather that the people who get college degrees have attributes (e.g. intelligence, work ethic, good K12 education, wealthy parents) that would lead them to out-earn their peers even without a degree.
To be clear, I don’t buy that argument. Obviously those factors explain some of the difference, but I think most of the highest-paying jobs in STEM and many of the highest-paying jobs in other fields (e.g. business/finance) require skills that would be hard to reliably obtain without a college degree or something similar.
Yes, that was my angle. And while I share your intuition to some extent, I maintain that it's difficult to get a scientifically sound conclusion without controlling for those variables.
Specifically, to refer to an average of $1,000,000 as a specific effect size, without controlling for the fact that many people with only a high school diploma would not earn more even if they had a college degree, seems suspect.
To be clear, I don’t buy that argument. Obviously those factors explain some of the difference, but I think most of the highest-paying jobs in STEM and many of the highest-paying jobs in other fields (e.g. business/finance) require skills that would be hard to reliably obtain without a college degree or something similar.