In the Corporate and Business Strategy world, there is a saying that "the only strategy you have is what you are doing." The previous assertion expresses that a pretty strategy deck, sitting on a shelf collecting dust, is not a strategy because no one is following it.
In a similar vein, the only product positioning a product has is the one that is expressed in published assets. It is politically convenient sometimes for product marketers to step back while copywriters trample over them because it is easier to do nothing than resist. We have all experienced these copywriters, the kinds of people who believe they understand all the current buzz but know nothing about the products, services, technologies, or uniqueness of the product, and they certainly have no idea about the positioning or regard for it; they are off in their world.
Sometimes, copycreators answer to a higher power than the product marketer, for example, the VP of brand strategy. Ok, we all have a boss, I get that. However, understanding does not mean resolution. Suppose a brand group does not understand or have regard for product positioning. In that case, readers will find they don't know much about Brand positioning either - they are like any other political agent asserting eminent domain.
Positioning to copy is as essential as Strategy to execution. The ideas are essentially the same. A company is what it does, not what some ignored group intended it to do. Whether through influence or control, positioning must be reflected in the copy; the copy is not an island separate and distinct from it, and marketing departments that believe it need a shake-up.