> All of which were blatantly mismanaged

It's easy to be a monday morning quarterback about management. Even so, no company is immune from blatant mismanagement. It's not a no-brainer to effectively manage a large corporation, not remotely.

For an example, look at Apple in the 1990s. A series of CEOs were all unable to get the company moving again, until Jobs was asked to return. (And those CEOs were all experienced and well-educated businessmen.)