Having a failure of parental upbringing and education system causing someone to be incarcerated seems cruel. Should a child who ran away from home & school to avoid family abuse be incarcerated? There are so many current systems of society (education, police, disability, etc) that have failures at the margin that adding incarceration seems over the top.
Yes, we should implement this as it’s never been tried before! Oh, wait…
https://en.wikipedia.org/wiki/Literacy_test#Voting
Perhaps instead of reading’, writing, and ‘rithmetic, maybe we should test one’s knowledge of history, eh?