Got-ya videos mean nothing. But stats like that one above certainly do mean something. The lack of classroom discipline plays a part here.
But there is a second problem. It's the idiotic educational fad called "teaching higher level thinking skills". Memorization is now not just frowned upon, it's forbidden.
So teachers are no longer allowed to emphasize facts. Instead students get questions like: How would a Civil War affect poor families?
Facts like who actually fought the war, who were the top commanders, etc., are no longer important.
Much the same thing occurs in math classes! In my district, math teachers must give FULL credit to wrong answers, as long as the "thinking" behind the answers meet certain guidelines.
My parents got a better education in the 30s than kids do today.