A project isn’t finished when the technology goes live
Go-live shows that the technology moved. It does not show that anyone can run what it became. Plenty of programmes pass the first test and leave the second one open.
Operational acceptance needs a named service owner. That person should be able to point to the risks and actions still open, the documents that are actually current, and the support model for an ordinary weekday, not just the cutover weekend. Monitoring belongs in that picture only if someone is expected to act on what it shows. Early-life support is the stretch where the project is still accountable for how the service behaves.
Handover into day-to-day operation is a decision. It names what is finished, what is owned, what remains, and who accepts the residual risk. If that cannot be written down, the change has reached the point where the technology is on. It has not finished.