GRRM confirms relationship with House of the Dragon showrunner is "abysmal." Why does this keep happening?

So today a new interview with The Hollywood Reporter dropped, and George R.R. Martin didn’t hold back. He explicitly described his relationship with showrunner Ryan Condal as "abysmal" and "worse than rocky."

This begs the question: Why the hell are fantasy TV writers so prone to their own ego?

We saw it with The Witcher. We saw it with Wheel of Time. Now we are seeing it with House of the Dragon. Showrunners seem obsessed with "fixing" source material that is already successful.

To me, it feels like a toxic mixture of incompetent writers getting jobs that require them to rewrite complex source material they simply aren't capable of handling, and their own egos inflating the moment the show takes off.

What baffles me is why studios keep making the same mistake. They hand immense power to showrunners who treat the source material as a "rough draft," all while sidelining the original creators who are right there willing to help. We see it with Martin, and we saw it with how Brandon Sanderson was ignored.

Why do studios keep handing the keys to writers who can't drive the car, while the person who built the engine is sitting in the back seat?