Not sure about that. I would read for fun instead of reading the assigned reading. The teacher would get mad. I'd continue to ignore them and continue reading my book.
So you can't just blame the teacher. If the books give you something essential, you'll turn to them to escape a harsh reality.
When your teacher criticizes you for not reading the boring book he/she ordered you to read, you stop enjoying reading and stop reading.
I've read more books than most people, I think. I certainly was in the top percentile by the time I was 18.
I never once read a book start-to-finish that a teacher assigned to me. When I had a book on my desk that I went out of my way to find at the library on one side and then some random book my teacher thought was good on the other side, I picked my book every time. I'd half-heartedly skim through their book and struggle my way through reading quizzes. The only saving graces were Cliff's Notes, film versions, or if the teacher outright read us the book out loud.
At least in our school district, this is not how its done in elementary school. Teachers don't assign books. Either it's completely free choice, or fiction/non fiction, or genre (e.g. mystery).
When I last read about this, it was blamed on 4th grade being the time when you shift from reading just to read, into reading to learn.
Required reading of books I couldn't relate to played a big role in me stopping reading for fun but I don't place that blame on my teachers for it. I doubt they had the freedom to choose which books we were assigned or whether we were assigned books at all.
School largely ruined my interest in reading until I became an adult and re-found it.
Being regularly told to read boring books, of course any interest in doing it casually was going to go out the Window.
Sure there is value in needing to read certain things from an academic standpoint, Beowulf is a good example. But there was zero reason I needed to read "The Outsiders" when we just watched the movie after reading it anyways.
Just because something is a classic, doesn't mean we have to consume it in its original form to get the meaning.
Instead fill the library with a diverse collection of books, let the kid choose what they want to read, don't rush them, and importantly if it just isn't working let them move on to a new book.
Side note:
I know some people are going to groan at this. But seriously, books based on video games can be a fantastic gateway towards actually caring about reading. It is how I re-discovered by interest in reading as an adult.
When your teacher criticizes you for not reading the boring book he/she ordered you to read, you stop enjoying reading and stop reading.
It's the teachers' faults.