99% of brands have an anti-social offering on Facebook - a social platform.
Promoted posts: Users are looking for user based content and interactions - not a brand post = negative views of the brand. And the image ad units - not much room for storytelling.
What can be done to improve? Understand that storytelling is not about capturing likes but to influence and create advocates who use your story to tell something important about themselves. That´s how you become part of the stories between people.
The problem is that 99% of brands are not doing storytelling. They are talking about their attributes. Not very social...