Why do governments everywhere have to be so full of fail?

I know this is rhetorical, but there actually is an answer!

Pournelle's Iron Law of Bureaucracy states that in any bureaucratic organization there will be two kinds of people: those who work to further the actual goals of the organization, and those who work for the organization itself. ... The Iron Law states that in all cases, the second type of person will always gain control of the organization, and will always write the rules under which the organization functions.

Or, in a less sf-writing-asshole and more sociological manner, there's Crozier.