This is how many municipal electrical utilities are operated. Essentially as independently run entities. It's actually worth pointing out that many government bodies are overseen by politically appointees (library boards, parking commissions, liquor control boards, etc.) creating a space in which civil servants are working with much more direct civilian oversight. As lampooned as this is in comedy (see Parks and Rec or Yes Minister), it's generally a fairly effective check against what you are speaking of. My library, for example, has a fairly robust law enforcement inquiry policy set by its board.