Scaling paid media is mostly an exercise in finding the point where it stops working. Most teams find that point months after they crossed it, because the dashboard kept looking fine the whole way.
The pattern
The shape is consistent and it is easy to miss. Budget rises. Platform return holds roughly steady, which reads as stability. Contribution margin falls. Steady platform return during a budget increase is not a neutral signal — it is what buying demand you already had looks like from inside the dashboard, because the platform claims the sale either way.
“Flat ROAS while spend doubles is not stability. It is the sound of you paying to reach people who were going to buy anyway.”
An account in this state has usually never run a geo holdout, because there is no moment at which the dashboard suggests one is needed. The ones that have run it tend to have run it once, and stopped when the result was inconvenient.