There's also the fact that many-if-not-most hackers are... shall we say... "unsuited" (in terms of their temperament) to the kind of work environment found in government security agencies. Let's just say that your tolerance for pointy-haired administrative BS had better be pretty dang high (like, somewhere between "ISS" and "Earth-Moon L1") if you're going to go down that particular professional path.
I imagine the NSA is well aware of the correlation between "very clever" and "difficult to work with".
I know people who work for GCHQ, and while they never talk about the work they are happy that the managers keep them insulated from the PHB stuff.
Very real. Best hackers spend their time hacking, not trying to get grades or climbing the hierarchical ladder.
Just think of Steve Wozniak, he was so afraid of not being able to engineer anymore if Apple gave him executive power. He refused to climb the ladder so he could continue tinkering in the lab.
In those big orgs the people that want to get power use to be sociopaths and "power addicts"(people that choose power over everything else in life).