As it turns out, the government actually has… the Government Accountability Office (GAO) as an agency to do just this. Agencies also have inspector general offices that focus on each of their respective agencies, too (Trump has tried to fire most of them, illegally). Congress also has the Congressional Budget Office (CBO), which provides Congress with budgetary advice independent of the Executive branch.

The US Government is too large to be perfect. But I suspect it probably works far better, at scale, with less variance, and more nuance, than many HNers imagine.