Doesn't explain the high level of competence, though.
The fact that private sector can pay much better than the government can seems to explain it neatly. Concepts like honor and service to your country doesn't pay the bills as nicely as selling AMZN.
This may have been true two decades ago. Now AMZN’s biggest customer is the government
I would argue that that's half the problem. The other would be the incentives that govt workers have to excel. Where I am (not the US) , the government jobs have a reputation for cushy roles, where your progression is basically guaranteed.