I have found for many young kids lack of studiousness is not that they are not self-motivated. It is that whatever is being taught is worse than boring to them. The lack of motivation in schools comes from a lack of interest or too slow of pacing.

By the time they get out of primary school most have had the curiosity that drives motivation beat out of them.

Yet, when I go through the skills and knowledge acquired during my school education there are many bits in there that I am now eternally grateful for, that I did not understand the need for as a kid.

I am not sure where I would have ended up if left to my own devices, e.g. as a kid starting first class I was bad at languages and hated it with a passion, in the last class I had the single best German and English final exams in my school district and language had grown on me.