Alice would make a lot because she's billing as a consultant that evaluates needs and produces a working, scalable, "runs itself" solution. She's not being paid for making WP sites, but for identifying that your complex needs can be satisfied thereby.

It's like the old joke, "I'm not billing you $500 for tightening a screw; I'm billing you $500 for the expertise needed to recognize that that was your problem."

(In my work, there have been times when I spent a week working on a problem and ended up with pull request changing only five lines, but it took a lot of research to find out exactly how to change those five lines.)