Litigation/malpractice probably plays a role too. I imagine doctors are under a lot of pressure to do everything by the book. If it works, awesome. If it fails,

Litigation/malpractice probably plays a role too. I imagine doctors are under a lot of pressure to do everything by the book. If it works, awesome. If it fails, they can say they followed best practices and it's not their fault. If they deviate for any reason, they do so entirely at their own risk if/when it blows up in their face. It's just not worth it (in the expected value sense) to step out of line.