Most of the people in IT in government have been around far longer then 9 months. While I move around on average every 3 years or so to keep a skill set current and move onto to other projects or opportunities, many, if not most, of gov IT has been around for years and years in the same place.
Are there managers that do that BS firing because they don't like people? Yes. Are they the minority? Yes.
Does the private sector have places taht take advantage of IT work force? Absolutely. Does the private sector pay more, yes.
If you're competent and willing to take a little less for the lifestyle differences, there's no problem unless you end up with a poor manager. When in state government I basically use very little time management when running projects as long as people meet expectations otherwise because its one of the few perks I can give. But your post reeks of a single or few experiences. I've seen way too much of government at all different levels to believe I just have seen the exceptions time and time again. Also, you've missed the point of firing certain people. Certain people are not qualified for the job they are in. They don't have the grey matter or the desire or a bad attitude or all the above. When you ask a person that's a .net programmer if they application had a separate business layer and data layer and they can't tell you because they don't know what that means even though they wrote the app, and that happened to me a few months ago, it's not a good sign. And someone that you need to figure out why they don't know what they should know. Too much of government employees are fat resting the laurels of the few. And they cannot be easily fired at the fed level nor in most states unless they are management. It takes dedicated management which, surprise, is usually where they tuck the competent techs to get them the salaries needed to keep them around and have them focus on tech not management.