I spent a decade administering a version control database depot for an IT dept of a billion $ software company. Despite numerous efforts by lower level staffers including myself, no code reuse project ever got off the ground. Redundant code is being written to this day, while the company upper management whines about the costs of the IT department, forces layoffs and exports jobs to Bangalore. Why?
Rush, artificial deadlines that are never met anyway, emphasis on projects that benefit directly and immediately customers outside of IT, the yes-man corporate culture. For the same reasons the code is written undocumented using unstandardized variable names. I tried to promote code reviews? Are you kidding?
At the same time, believe it or not, the engineering department which produces the company’s products adheres to strict standards of coding, code reviewing, release management. Go figure.