@Canoehead: I agree there's no physical or financial reason why something this big couldn't be built in America, but I think this country has lost the will and ability to carry out big projects.

The US managed to put men on the moon in a decade, but it's going to probably take 2 decades for them to build the San Francisco to San Diego high speed rail they're talking about (if it ever happens).

As you say there's NIMBY and various legal hold-ups, but I also think the public doesn't have the stomach to spend their tax payer dollars on long-term infrastructure projects (if they can't see the benefits within a year they're unhappy) and corporations won't invest in anything that doesn't have a near-term payoff (partly because the way executive compensation is tied in to the quarterly or annual bottom line).