Optimization is a habit, not a project
A one-off audit is out of date the day after the next deploy. Cost drifts back the moment nobody is watching, and nobody is watching by default.
The answer
The cleanup sprint: why the bill comes back
It works — for about a quarter. Then the drift resumes, because what you fixed was the symptom and not the process that produced it.
You paid an engineer to not build
The person auditing the bill is the person not shipping. That is a real cost — it just does not appear on the invoice you were trying to shrink.
What GIIP FDE Ops does instead
Cost optimization runs continuously as part of operations, not as a quarterly fire drill. Rightsizing, cleanup, and scaling decisions are handled alongside the deployments that cause them, under governance you approve.