A model that answers well in a sandbox tells you almost nothing, because production failure looks nothing like a wrong answer. It looks like an integration surface the model cannot reach. Two systems whose fields share a name but not a meaning. An approval branch the demo never exercised. A permission boundary that works only for the engineer who built it. An upstream schema that quietly moved in June, three months after go-live.
The role invented to close that distance is the forward deployed engineer — someone who sits inside the business, learns how it actually operates, translates that into something buildable, ships it, and owns the outcome afterwards. It works. It is also headcount: every enterprise is hiring for the same scarce people, capacity grows one engineer at a time, and the context walks out the door with them.