I worked for two mom and pop airphoto mapping shops that could be called "private enterprise", but about half their clients were state and local government agencies working on municipal construction projects. I also worked for a non-profit corp that provided liaison and support between the Federal government and the nuclear and utility industries. I worked for two defense contractors in Silly Valley. And I worked for a major oil company--using satellite imagery provided by the Federal government.

Now that I work for the "public sector" I can see that most of what I do can actually be traced back to as a service (and convenience) for private contractors and developers.

I'm convinced the major division in society is not between private and public sectors, it's between guys who shower before they go to work in the morning, and those who shower
after they come home in the evening.