Government using people's taxes to waste money with 0 accountability
In practice what the "small government" ideology actually does is get rid of these accountability mechanisms and put scammers and corrupt people in charge instead or relabels corruption as the policy through public-private partnerships.
Furthermore, nothing prevents applying these oversights over public-private partnerships (which is just a fancy term for outsourcing). The government decides who gets hired and on what conditions, so it can just enforce transparency requirements.
Those companies that win big pork filled contracts would never have any incentive to get the company to waste tax dollars.
Adding the profit motive in here definitely helps prevent waste