What was considered vital information for schools in the 19th century and what is considered vital information in the late 20th or 21st century are very different things.
Obviously the test is heavy on written grammar. While that would make some people's posts easier to read, it isn't as critical as other skills. Also, genders were educated separately, because girls were thought to be less clever, and didn't need a "real" education.
And since most people (especially in the US) spent their entire lives within 25 or 30 miles of where they were born, there was less interaction with any other cultures.
Read Future Shock by Alvin Toffler. It will show the torrential changes in our world in the last 100 years or so. The book was written in 1970. But one thing that stood out to me was the result of a timeline for humanity based, not on years, but on technological advances that changed our lives. The +/- 50,000 years of human existence, if put on such a timeline, would have the middle set at around 1900. In other words, those kids taking the 8th grade exam in 1895 lived in a world more like ancient Rome than modern times.
The test is interesting, not as a mark of intellect or education, but as a view of how much the world has changed.
As a bit of anecdotal evidence, back in 1996 my grandmother turn 90 years old. My oldest son (10 at the time) and I drove her back home after she spent a few days with us. I encouraged my son to ask her about her childhood. When he asked her about the biggest change she had seen, we expected her to say radio, tv, electrification ect. Nope, it was the roads and highway. Something so common to us was a virtual miracle she had seen develop in her lifetime.