I am not so sure you can build an economy of scale with projects that take a decade to construct and even longer when accounting for approvals and paperwork. The projects are too massive and too long. The contractor that poured the foundation for the last project may no longer be around. It has worked in some areas of the world like China because they have been building from zero and are able to scale mega projects.

The US has more hope to learn by iterating on smaller projects.