Expertise Not Discovered Until Almost Too Late

This story comes from the military. We had an NCO who was considered mediocre in his technical job and transferred to a Training Unit, where he could be out of harms way until he retired. This guy turned out to be expert at databases and he ended up creating an online training system. It became the standard system for the whole organization, after it was recognized externally and won awards. His expertise was not visible or valued (even to himself) until he got the right job. His expertise in his original role was not valued. This happened in his 19th year of service so he then retired, and his expertise was lost almost as soon as it was found. He resented being given his original job. Moreover, it was an external party who recognized his accomplishment first, and not his commander.