Your section about the WordPress landscape being diluted with users who are confused about where they stand in terms of development ability is spot on, and I feel is partially to blame for the major gap in salaries between a WordPress-centric position vs not. I also feel its to blame for the rates clients expect to pay to have a WordPress site developed for them.

As you mentioned there are users who claim to be developers who purchase themes from theme marketplaces, throw up some content, swap out some images and charge an exorbitant amount for something that can be completed in a few hours. I'm not saying there's something wrong with these users, and they certainly have a place in the community, but to label themselves as 'developers' is counter intuitive and a label used solely to raise rates. I've had my fair share of clients come to me after dealing with someone who said something couldn't be done, just because they didn't know how to.

Great article and a great read.