Because not everyone is just out after earning the most money, some people also want to enjoy the workplace where they work. Personally, what the quality of the codebase and infrastructure is in matters a lot for how much you enjoy working in it, and I'd much rather work in a codebase I enjoy and earn half, than a codebase made by just jerking out as many LOC as possible and earn double.

Although this requires you to take pride in your profession and what you do.