Large public works projects in the US

Been watching the History and the Discover Channels recently... and come to the conclusion that as a society we (USA) no longer build extremely large public works projects. Look at the types of projects that were built in the 40's and compare to what we could build now with our technology. Have we as a society, quit reaching for the projects that are barely within our grasp?

Mackinac Bridge
Hoover Dam
Chesapeake Bay Bridge

These types of projects, motivate and unify us as a society. They are a source of national pride and celebration.

Europe built the "Chunnel", China is building the Three Gorges Dam, why is the North American society, not building these types of projects?

The Big Dig in Boston may have been close but it doesn't have the sex appeal of the other larger projects.

It's the decline of Western Hemispheric power that is causing it. However, if US were to actually follow through with the Orion Program, then things could change quite quickly.