Why do animators of “episodic” animations insist on recreating the books and not their own stories with new OCs?

This is a subject that was on my mind after the last animation of Into the Wild but there’s honestly been a few over the years. I don’t understand why animators put so much work into recreating the books plot point by plot point when it will enviably get axed. Could the team not just write a story about their own clan with their own personalities and lore? We have like the millionth Into the Wild Episode 1 of Rusty in existence and I don’t think we need any more.

It seems like me that Erin Hunter has no qualms about creators animating their own fan works as long as they don’t follow the books’ plot directly. This is why we have short animated clips on YouTube all the time and a tons of fanfics and fan games. But why has there not been any animations that animate an OC story or a fan clan? The only thing I can think of is Crowpaw content that I see from a creator on Youtube but they mostly MVs to music and not the same as an episodic animation.

I can’t think of an episodic animation that DOESN’T follow the first book exactly. I know that animating takes a lot of work but a lot of studios just work on the same Into the Wild remake and then get disbanded when that time and energy could be put into something more creative that might last? The only problem I can think of is who owns the ideas when there’s an internal fight but I’d prefer an episode 1 or 2 or 3 of something refreshing than Into the Wild done YET AGAIN. I have never seen someone else state this opinion in the fandom but I can’t be the only one who thinks this?