Maybe because it's BORING to the average person!
Maybe because school children didn't have good enough teachers to actually teach it!
Maybe because it's thought of as 'toffee nosed' writing.
Maybe because very few people are interested in it.
Maybe because so many people can't UNDERSTAND it, so refer second line above.
Maybe because State School educated children perceive it a subject ONLY for Private school students!
My Poetry book for Grade XII was 'The Poets' Pen'. I enjoyed the majority of poems in it. My Grade X book, I forget the name of it, but can still picture the front cover's gold/yellow picture in my 'minds eye', but I do remember it had heaps of poems about Australia, there was even one poet whose daughter was in my class!
For my reading enjoyment, I find Shakespeare's Plays each, one very l o n g poem!