So?...Where do you think that we would be as a nation if there had **never** been compulsory state run K-12 schooling? Do you think that Americans ( the most generous people since the dawn of humanity) would have allowed this nation's children to go uneducated? Personally, I don't think so.
I have known people who only had an eighth grade education--but they got that in the 50s. Even a mediocre student of that day, at that level, could run rings around the average pupil of today in terms of composition, grammar, and mathematics. The standards were that much more rigorous, and it was done without a calculator, computer, or the internet.
They took those basic tools and often did quite well.
(some) Americans took the time to teach others, whether they were friends, relatives, or employees, and pass on what they knew. If nothing else, it made getting things done easier whether that be on the farm, an industrial workplace, or just around the home.