Game developers usually don't want to see ultra high detailed models since it would never make it into a game. What they want to see is how good a model looks with the least amount of geometry possible.
Considering that the model I made, when the sketch was sent to me, they said it was for a PSP game, therefore the polygon limits.
Maybe for normal mapping you'd use HD models. but then again, its MUCH easier to make an insanely detailed model with Gigllions of triangles, than it is to make something decent under 1000 triangles
Just like the Chief in Halo2, if you look at the model without shaders, then with the bump map applied, you see a world of details you can get without the extra geometry.
[attachment=3930:chiefbump.jpg]