This excellent article from The Atlantic touches upon a fundamental reason why many in-house marketing pros are often better off outsourcing their writing assignments.
According to Megan McArdle, writing is something even natural wordsmiths tend to put off as long as possible. For marketers -- no matter how seasoned a writer one may be -- all the meetings and distractions of a typical workday make the act of sitting down well after closing time to draft a press release downright depressing. Why subject oneself to the additional headache?