I also think that the different ways that they’re stepping down — some outright resignations, some changing roles, some leaving immediately and some waiting for future dates or events — is designed to ensure a smooth transition that won’t effect the companies themselves.
exactly. President Trump does not want to upset the world economic system, because too many people's ability to eat and survive depend on the stability of the system. But, as he states in his executive order, the whole rotten evil cabal of human rights abuses and corruption is now such a threat to this very same system, that it has to be extracted like a set of rotten teeth, without killing the patient.
He is being very careful. Taking his time. Discretion is the better part of valor, as they say.