Or, you could argue that the government should be limited to market failures.
Roads, defense, control, vaccines... all have significant effects outside of the markets, and thus their price does not reflect the benefit to society.
Where do you stop? Surely you'd have to include financial companies? A financial company that makes up 10% of the financial market will calculate a phony 90% discount on any systemic risk it creates: after all, if the system fails, only 10% of that failure will be realized as a loss.
Roads, defense, control, vaccines... all have significant effects outside of the markets, and thus their price does not reflect the benefit to society.