A lot of these people prefer the stability of knowing their income over a long period of time, rather than focusing on maximising profitability and therefore losing time working on their craft and also introducing instability longer term. My job is similar to this sort of thing and I have gone down the maximising profit route, and even though I've not pushed it to an extreme it can be difficult to stay disciplined about it. You lose a lot of time to it, as well as intelectual bandwidth - you're bouncing back and forth between business brain and craft brain a lot more. Crafts people also tend to be more community orientated which likely reflects in their pricing.