Good old fashioned nepotism. People generally get into executive roles because of who they know, not anything they’ve done. Don’t get me wrong, you need some minimum level of demonstrated competency, but these aren’t rocket scientists we’re talking about. They are people who managed to finish an MBA without shitting themselves and then did time at some excel jockey jobs before shaking hands with the right person.
The reality is that actual good ideas are often threatening to the people currently in charge because it makes them look bad. Thinking outside the box is thumbing your nose at “what we know works.” It’s “rocking the boat” but what that really means is “wait your turn pleb.”