For the most part disease memes, like diseases, are self-limiting: depressed or defeatist people tend to eschew social interactions, and the healthier parts of the organization reject them and their beliefs. It is not uncommon during periods of societal financial stress to see corporations succumb to defeatism and collapse.
Various disease memes have more adapted life-cycles; for instance they make the carriers more effective when carriers are sparse. A simple example is a "yes man", who rises rapidly in a corporation until he is an executive. But a "yes man" cannot function as CEO, and a leader cannot function surrounded by "yes men".