> Virtually everything about the cohorts you're comparing are different!

Not meaningfully so. Life doesn't move that fast. There is only one year between when the average person didn't go to college and when the average person did go to college. More ideal would be to put the exact same person into parallel universes on those different tracks, but let me know when you figure out how to do that. In the real world, that is the closest approximation we can get. And what we were able to plainly observe is that there was no change in earnings.

Which is interesting as it pertains to your point as it is unlikely in a vacuum that two random average people would ever have the same earnings, so the fact that they landed in the very same spot does suggest that our approximation is much closer than it seems you want to believe.

> I have no idea whether there's an innate structure in people that's causally determinative of lifetime income.

Nobody does. There are plausible explanations, but we have no scientific evidence of what the "secret sauce" is. Which, with your recognizing that, makes your earlier claim of education influencing lifetime earnings even more ridiculous.

> I don't think this kind of faux-axiomatic reasoning can get you to the kind of certainty you have here.

You must have misread something as the only certainty I offered was that college hasn't lead to higher lifetime earnings for individuals, which we know is the case as we have comprehensive income data to prove it. You cannot both earn more and earn the same. Someone with high lifetime earnings, statistically, also having a college education is not the same thing.

There is one caveat here. We can see in the data around the top 1% of earners that the majority of them have access to a restricted market (think doctor, lawyer, etc.) which most people legally are not allowed to participate in. As you know from Econ 101, an artificially restricted supply artificially increases prices, so that offers a pretty good explanation for how they are able to earn so much more than everyone else.

Here's where things get messy: Access to those markets is often granted through the colleges. That might be where you got the idea that education influences lifetime earnings, but we find the same economic benefits where access to restricted markets is given outside of colleges as well. There is little evidence that college is signifiant there—only the access part. But I can understand your confusion if that is what you had in mind, conflating it because colleges also try to offer education.