My slightly-better-than-anecdotal feeling is that the amount of academic knowledge that is actually learned is very low. I base that on what my (biological) kids said, and what my students said. “You can’t expect me to remember that. We did that two months ago.” Like I had tried to tell him that water wasn’t wet. Also my experience that you couldn’t expect students to know what had been done a unit or two back.
True story: I’m teaching Honors Physics and we’ve come to resolving vectors into horizontal and vertical components. It requires basic trigonometry (sines, cosines, and tangents). I’m telling students how to do it, they look puzzled, and one student says, “We never did this.” The rest of the class agrees: they never did sines, cosines, and tangents. So on the fly I do an “introduction to trig” and when I get home do up a handout with definitions and diagram and justification and a number of problems. After school the next day, the previous year’s Honors Geometry teacher comes into my room. “If anybody tells you they didn’t do trig, tell them to come down to my room and I’ll take five points off their final grade.” And he slaps down on the desk eight basic trig worksheets, all of which they had done the previous year. Now I don’t know if they totally forgot doing trig at all or if they had just forgotten the substance and wanted a review/reteach. But few of them were ready to do vector resolution. From then on, I made sure to begin vector resolution with a substantial review/reteach.
But maybe the fact that young people don’t learn much in the way of academics isn’t actually a problem. After all, one of Caplan’s points is that very little academics is used after graduating (unless you’re a writer or academic or something similar). Maybe much of the human capital they develop (or talent they signal) is willingness to put up with, and even put some effort into, things they aren’t interested in, maybe even don’t like — and do what has to be done to pass. To mimic you, that sounds like a lot of jobs.