Because candidates are not aware of the environment they get in to, or have not experienced such an environment. You don't know the company's language yet. You

Because candidates are not aware of the environment they get in to, or have not experienced such an environment. You don't know the company's language yet. You think you heared A at the interview, and you are not getting A. "They use continuous integration and deployment" which in their terms is a custom ant-based build system of 3000 files, while you think they use Jenkins with Maven. Bonuses and raises are one part that influence the scale. Colleagues, maintenance work, difference in code style, heated discussions, way of working are another.