Your website's goal is to generate value, and by extension build interest and trust in your brand. Whenever you hire an outside agency to fulfill that goal, you assume that agency's content strategy is in-line with your own. That's not always the case.
The colossal issue holding back so many businesses is that their blogs don't sound like they were written by a person, or written for a person. I think a huge reason for the abundance of stale content is that people are deathly afraid of breaking "The Rules."