The entrenched political class and those in (inevitably self-serving) government positions. See Pournelle's Iron Law of Bureaucracy.

The state, much like corporations, are operated by individuals but are not really "made up of" individuals in the way that your statement implies. They are machines that have their own goals, interests, and methods that are distinct from those of any of the individuals who help operate them.

Individuals may only be seeking more power to better do their jibs and serve to the benefit of the people.

But bureaucracy is just so evolves that it perpetuates the problem it was created to solve. Trivially, those agencies which reliably have achieved their goal get disbanded as no more needed, the only remaining in the long term are such whose goals are elusive.

This is how well-intentioned, honest people try to grab more power for their agency, because it seems to help achieve that elusive goal.

(To say nothing of people with less integrity in a position of power.)