The main problem with Feds is their unwillingness to do the work of firing unproductive or insubordinate employees. It can indeed be done, but involves work for management.
About 1-2 years was the norm where I worked. It's an administrative nightmare that usually ends with a lawsuit and a settlement. It costs the gov't a lot of time and it's never cheap.
The last private company I worked for went bankrupt and they changed the locks on a weekend. That was our first clue.
