What are disadvantages of monopoly?

Note: these arguments are normative to a large degree, and constitute the opinion of some authors.

1. Oligarchies form uneven relations of power and, in doing so, use state power for their own ends and not to the betterment of the public.

2. Oligarchies do not grant even access to the state and, in doing so, may be procedurally unfair, especially if people have a moral reason to have access to the state.