It's hard to draw meaningful conclusions form a single 4 year period. There have been several instances of corruption (and significant externalized costs) in private firms that went on for much longer than 4 years.

I agree that there is a lot of corruption in government but there's a long gap between that and no accountability. We see various forms of government accountability on a regular basis; politicians lose elections, they get recalled, and they sometimes even get incarcerated. We also have multiple systems designed to allow any citizen to influence government.

None of these systems and safeguards are anywhere close to perfect but it must be better than organizations that don't even have these systems in the first place.