Upvote:6
According to this government site, illiteracy has been shrinking almost steadily from 1870 on (with one little hiccup between 1947 and 1950). According to Wikipedia, the US had a very high literacy rate in 1870, and this was during the creation of a national public school system. With increasing school availability and legal requirements to attend, it appears that illiteracy has gone down.
Therefore, the question has factual inaccuracies. The current illiteracy rate is very low, and has declined during a period of expansion of public education.