To be fair, the only example "where they left" is AES, where the leader was forced out by the shareholders and replaced with a more traditionally minded leader,

To be fair, the only example "where they left" is AES, where the leader was forced out by the shareholders and replaced with a more traditionally minded leader, so it's not the leader's absence which caused the reversion - or at least we can't know for sure. The other examples don't show a leader leaving and the company reverting to traditional top-down, as far as I can remember.