Make it mandatory across the Federal Government no one can be assigned to D.C. / "Headquarters" for more than 10 years.
One would hope as a new employee your first assignments would be in the field. Here you would learn your craft, the in's and out's of your job and the organization in preparation for advancement to positions of greater responsability.
Once you have experience, and are assigned to D.C., this is where you develop policies and procedures based on what you have learned in the field.
IF your career is over 20 years, you go back to the field where you will see how the policies and procedures you developed are being implemented. Here you will see what works, what doesn't, what needs to be tweaked.
Ensure the people who are put in the position of Leadership have "earned their spurs" before given the responsability.