Many people hate change; contemplating the unknown is scary. So many stick with familiar things even though they no longer fit. This is especially true of careers. Sometimes people get stuck in a career direction or work environment that makes them terribly unhappy, and they stay there because it's tough to change careers once you have gained experience, power, and good compensation.
People often end up in the wrong careers by accident. They start out with a job and become proficient, so they advance and make a good living. They may even start a company in that field. They get so focused on growth, meeting objectives, or making the money to support their lifestyle, they don't realize how toxic their life has become.