I think most of us would be surprised if we read the book. As far as my writing, I graduated in May with my Masters. I wrote paper after paper after paper. I always had a friend of mine (English Teacher) proof it. It did not matter how good I thought the paper was she always managed to find something.
I think grammar is becoming a thing of the past. Right now in middle schools the main focus is reading. I am not sure about the lower grades.