Humans are prone to cargo cult thinking. Presented with a successful or important person, we automatically copy their behavior, because their behavior must have made them successful or important.

I think that this is why usage of stupid idioms and phrases flows downward in hierarchies. Have you ever noticed an executive use a corpspeak phrase in an all-hands meeting and then seen it crop up immediately afterward in e-mail and meetings from lower-level management? It can be fun to ask them what a new phrase means in real terms, too -- often they don't really know.

For all the talk about American individualism, American corporate culture is actually extraordinarily collectivist. The pervasive groupthink at all levels of the hierarchy is an effective survival strategy. It's quite depressing to read accounts of individuals who lived under the boot of various collectivist regimes, particularly the modes of thought and expression so prevalent and necessary in such societies to keep your family from starving, only to realize that they are more or less replicated in American corporate environments, for more or less the same reasons.

Promiscuous middle managers and C-Levels? I'm thinking they carry a heavy load, shed a lot, really get around, and frequently attend superspreader events.

People who work at companies tend to keep working at companies. You don't get as much movement going from McDonalds to Google, but tons of folks migrate among tech companies. So the culture naturally spreads.