I believe this is due to a combination of everything you've listed (plus apostasy exhibiting itself in fiction wouldn't be a stretch of the imagination). Additionally, I know for a fact, having taken several writer's courses, subscribed to various writer's magazines and purchased quite a few books that advise writers on the topic of the best routes to publication (all secular), that writers are routinely informed that the #1 way to gain publication (and especially to get that first publication) is through Christian writings/publishers.
Originally Posted by Nightelf
Do not store up for yourselves treasures on earth, where moth and rust destroy, and where thieves break in and steal. 20 But store up for yourselves treasures in heaven, where moth and rust do not destroy, and where thieves do not break in and steal. 21 For where your treasure is, there your heart will be also. ~ Matthew 6:19-21 ~