God that's one of the most pessimistic views of humanity I've seen on the web, and I'm pretty pessimistic. Developed nations have a 99.2% literacy rate per wikipedia. 69% of OECD students meet "level 2" mathematical proficiency (https://www.oecd.org/en/topics/sub-issues/mathematics-litera...), which indicates an understanding above the basic mathematical operators like multiplication and division.

FWIW I did not go to any fancy school, I was educated in the state system.