Front-end systems have more room for creative expression, drawing in more of those who want to express themselves with a major overhaul. Furthermore, the base s

Front-end systems have more room for creative expression, drawing in more of those who want to express themselves with a major overhaul. Furthermore, the base skills of front-end developers are more of "understanding how humans interact with user interfaces" and managing complex state. Back-end developers tend to need more understanding of the problem domain and communication skills, so the developers that do better at back-end work tend to build things that need less updating. Basically, I'm asserting that front-end and back-end work attracts different kinds of developers. Back-end developers are less likely to write things that need replacing, and front-end developers are more likely to want to replace things.