Well, THAT'S an interesting theory. Not one I would ever be inclined to test, though. Seems like a serious waste of material and effort.
It is true that there is a certain amount of skill involved in laying track on grades dictated by still-imaginary terrain, but I think that is one of the core skills of layout building. And, as Mike said, modern CAD systems make the whole process a lot more accessible to the spatially-challenged.
