well, i am not prehistoric, and quite young.. (i havent't been 47 too many years, more than 1, but not an unreasonalbe number!, when i compare myself to people who self define themselves as geezers!

and i learned sentence diagraming in school.

but i will admit, when i transfered from a catholic HS to a public HS (mid term), and entered the english class and was called onto name the parts of speech in a sentence on the board, i diagramed it.. and the teacher looked at me, and at the work, and said, "Helen has done a fine job, and it perfectly correct, though i realize none of you understand her process, how about you, XXX, can you come up and label the parts of speech?"
(and so i learned that not everyone diagramed sentences.. and i used older, out of style method)