Yeah, kids are not born smart, they learn for the most part from their parents and society. I read that it is crucial to teach kids all basic skills by the age 10, if I remember it right. Even the people who were raised by wolves couldn't learn basic things if they are over that age. But parents have no time because they are overworked and the society has the institutions like school and mass media that teaches what the ruling class wants you to be: do not question anything, do not protest, don't be too smart, accept consumerism etc.