This is called being risk averse and this tendency is a genetic trait to help propagate the species. I once lived in NYC and worked for a large government agency that had maybe 150 architects. Most were talented, very intelligent, and miserable in their jobs. They always complained that they were on an assembly line just re-creating the wheel everyday and had no outlet for their creativity. When I asked them "Why did you take the job?". They always answered "The security". None of them felt like they could quit at this point because they had too much time invested where they were. Too much to lose. They would rather count the miserable days until they retired instead of taking a risk and possibly being happier in their profession.