You know how teachers are too lazy nowadays to teach kids how to handwrite? What do they call it, cursive. Also, in high school geometry, teachers don't teach rigorous proofs. Man, other than proofs, geometry was a lark. Proofs separated the men from the boys.
Well, the same phenomenon existed many decades ago, when lazy teachers stopped teaching 6th-graders how to diagram sentences. That's why despite 8 years of writing college papers, they didn't teach you the difference between a verb and a predicate.
Bring back sentence diagramming!