I am assuming that it's the public school system we're talking about here. The $20,000 is from our taxes. You can very well choose to stay at home and educate your children yourself and pocket the $20k, if that works for you. In my opinion, we seldom learn everything from 1 or 2 sources. You can provide your offspring with math & science but what if your offspring is also interested in music, language, literature, drama etc.? Or any other subject that is not offered in the school system?

I am just advocating for the child. As parents we're in the best position(mostly) to judge what our children's needs are.