I genuinely think that the vast majority of English teachers have had experiences like this. It's what made them become English teachers.
Then, with all the best intent in the world, they try to explain to their students "Look, you don't get this, this fat book is transcendent if you can just sit with it and understand it! I, too, used to think that English class was just stupid words that they force you to read, but let me help you get this! You've got to..."
But all their students hear is Charlie Brown's adults going "Waa waa waa..." because they're genuinely not mature and experienced enough to "get" the book the way the English teacher understood it.
Ten years later a student will re-read one of their literature books, have this same epiphany, and talk excitedly about deep literature is, and someone will tell them they ought to be an English teacher. And the cycle continues.
Ok, so some English teachers are of course better than others, and some will convey their excitement a little better, and some students will be mature enough to understand it better than others.
But I will definitely maintain that all (close to all) English teachers have this same love of books, and want desperately to pass it on.
I think this is one of the more important points in this thread.
The problem is that too many pieces require experiences that the majority of the classroom just doesn't have.
It's not that students don't venture far enough into the cave to find the treasure, it's that the treasure literally isn't treasure to them yet.
The venturing that needs to happen for them to find the treasure isn't time spent in the material, it's time spent gaining life experiences.
Ex - there was nothing you could have done to make a book like "The Great Gatsby" good for me as a 15 year old. It's filled with themes that I had no experiences to connect with - no lost romances, no wealth (or even really a sense of wealth and money), no major life regrets, nothing at all to make this book hit. It's a dreary book about miserable, unlikable people when read from the perspective of a 15 year old student.
So why are we asking 15 year old students to read this book?
And that doesn't mean we can't throw students in over their heads every now and then (ex - exposure to the unfamiliar is fine). But if that's all you give them... they decide reading is pointless. You have to strike a middle ground with material that hits home.
And there's a range of teacher quality here as well - some are genuinely good at pushing students towards understanding the value in material, even if they lack experiences. But most aren't (at least in the US educational system I went through, which was a mix of decent public schools and expensive private schools)... they're passionate and well intentioned, but fail to empathize with the emotional maturity and world view of their young students.