People working in large organization have most likely heard about the field of Knowledge Management, and that there someone in the organization responsible for retaining and protecting their knowledge, to avoid the loss of this knowledge from the aging workforce. One of the books that talks about this is Lost Knowledge: Confronting the Threat of an Aging Workforce by David W. DeLong.
As people retire, they take out with them about 80% of the knowledge that they had when they were working is such a large organization. The big question is who is responsible for retaining their knowledge after they retire? Most likely, they are on their own! The Knowledge Manager that they used to have at the organization is no longer there!