Having worked for both, I would say that most government offices are eternal, whereas private companies can vanish quickly. Sometimes without warning. Its really hard to kill a government office.
Makes me wonder, how did a necessary office survive during a junta or an overthrow? For example, how did the office of a postal clerk change from 1925 to 1955 in, say, Berlin? How does the average Salvadoran DMV worker view the changes in El Salvador since 1980?
How was a tax office run in ancient Babylon versus a modern one today?
I bet there's some weird insights into human civilization to be found in those stories.
My understanding is that the more removed you are from the "top" of the government pyramid, the less you are affected by disruptions of that position. Largely when a new face or party takes over (by force or otherwise) very seldom do they want to rebuild everything from the ground up and will keep most of the bipartisan offices untouched.
If a very violent coup is successful and they're planning punishments for all "government officials" the postman in a rural village is going to be pretty low on that list.