It's all marketing really. Many of the devs who struggle the most have some difficulty giving themselves credit for things they've done - they're modest perhaps. I think when I write some of these resumes they are more accepting of them because it's me bragging about their accomplishments.

Unfortunately in the resume writing game, there are lots of failed writers that were never involved in hiring. They are good writers but don't know the audience, so people end up paying substantial amounts for a nicely worded resume that doesn't result in interviews.