I'm pretty sure he didn't have any drive to learn it and was just focusing on general studies like math and reading.
If you grew up your whole life only knowing tractors, its not unreasonable to believe that you would never think tanks exist if no one talked about it and it was never brought up to you.
He has experience from a previous life, he lived through part of adulthood in a previous life. He lived long enough through the process of learning and exploring that it’s not insane to think he could do it again. That’s again why I keep saying, please attribute it to being mentally broken as a person since other approaches are lacking.
As to your example, it only works if the one involved has no idea of machines in general, right? This means if you believe a construct is one ineffable entity and thus you’re better off just knowing its function instead of investigating it’s construction, it only makes sense that you don’t attempt to be curious. If he was a regular member of the world then it makes sense: he literally does not know that there is anything more beyond what he has experienced. If you only know a tractor and no other machine nor the concept of a machine, then why investigate further if a tractor is all that is necessary. By the nature of this story, that is NOT the case. He not only knows of tractors, but also of tanks, and also of machines. It would arise that a person who has knowledge of all but was unable to access the more powerful ones would investigate in a world where “metal parts” could be fabricated by will alone.
Do you see how starting a story with certain constraints, but then not addressing the logical approach to those constraints causes this issue? Once again, I have no issue contributing this to being broken and impacted, but in your case it makes legitimately no sense, he should have had this on lock for years.
