I actually intepreted that as the jobs require a very low level of skill and provide low compensation—exactly what you’d expect from making a job “blue collar”.

Most of the skill in that area is not working with the CMS but doing the crazy complex integrations that clients ask of them. (And of saving the work of not-as-skilled/too-skilled-for-their-own-good crowd.)

Maybe more of a light blue collar.

You can make very good money as a consultant in the PHP/Joomla/Drupal world if you are professional, reliable, and write solid, bug free code.

Nothing you make will be particularly interesting, but you will make an excellent living for yourself.

That is true, but you’re focusing on the php part rather than the median php position part, which is the relevant point to the discussion.