Thing is that's a question for the market to decide. Which is why we have anti-trust / anti-monopoly laws in the first place. We don't want the state setting "fair" prices for anything, it always backfires. We want them ensuring the market is free to set prices. Monopolies granted by the state (trademarks, copyright, patents) are specific and limited, and ideally we want monopolies that arise naturally to be similarly limited, or broken up if they are being weaponised against the public.