Therin of Andor wrote:
Perhaps the film's writers simply knew they'd be too busy to read four novel manuscripts while writing a new movie has not been laid out.
They wouldn't have to read the whole manuscript, just a general plot outline. Then they could decide "Reject, we plan on doing something similar to this in the next movie" or "Accept, we don't plan on exploring this idea and see no harm in a novel covering this ground." I doubt they're directly supervising every stage development for the YA novels or the comics, so they wouldn't have to with those novels either.