I am that person. Read Brennan's book in 2012 and im making 3-4x as much net today as I was then. Is it entirely due to that book? No, of course not, but it did shift my thinking and start me down a road of continually pushing the boundaries to charge more. Which I often feel I'm pretty terrible at, but at least I'm trying.

The set of freelancers working right at the rate they should be is orders of magnitude smaller than those who are far undervaluing their work because they've never even really tried to dramatically increase their rates.