Because as soon as you're 2-3 levels up it's all politics, no content. All information comes from people who know better than you. All execution is done by people who are better at what the company does than you are. The "base" level of playing politics, the table stakes, is to never get blamed. And there's regular fuckups who need guilty parties. Look up the 3 envelopes parable.

Let's put it this way: consultants provide a new envelope every 6 months or so.