Here is C. Northcote Parkinson’s terrifying and utterly convincing explanation of uncontrolled expansion in bureaucracy:
We may distinguish at the outset two motive forces. They can be represented for the present purpose by two almost axiomatic statements, thus: (1) “An official wants to multiply subordinates, not rivals” and (2) “Officials make work for each other.”
To comprehend Factor 1, we must picture a civil servant, called A, who finds himself overworked. Whether this overwork is real or imaginary is immaterial, but we should observe, in passing, that A’s sensation (or illusion) might easily result from his own decreasing energy: a normal symptom of middle age. For this real or imagined overwork there are, broadly speaking, three possible remedies. He may resign; he may ask to halve the work with a colleague called B; he may demand the assistance of two subordinates, to be called C and D. There is probably no instance in history, however, of A choosing any but the third alternative.
See this online version of “Parkinson’s law, or The Rising Pyramid”, the first chapter of “Parkinson’s Law, and Other Studies in Administration” by C. Northcote Parkinson.