Is California's $70 billion high-speed train obsolete before it is even built? A colossal waste of money?

With California and US taxpayers on the hook for $70 billion to build a train across the state starting this year, Elon Musk might have already made it a waste of money.  The government would have a slower, more costly way of moving people that few would want to use.  Musk isn't promising to make this system operate, but he is arguing that it could be done.  From Bloomberg Businessweek:

Almost a year after Elon Musk, chief executive of Tesla Motors (TSLA) and SpaceX, first floated the idea of a superfast mode of transportation, he has finally revealed the details: a solar-powered, city-to-city elevated transit system that could take passengers and cars from Los Angeles to San Francisco in 30 minutes. In typical Musk fashion, the Hyperloop, as he calls it, immediately poses a challenge to the status quo—in this case, California’s $70 billion high-speed train that has been knocked by Musk and others as too expensive, too slow, and too impractical. 

In Musk’s vision, the Hyperloop would transport people via aluminum pods enclosed inside of steel tubes. He describes the design as looking like a shotgun with the tubes running side by side for most of the journey and closing the loop at either end. These tubes would be mounted on columns 50 to 100 yards apart, and the pods inside would travel up to 800 miles per hour. Some of this Musk has hinted at before; he now adds that pods could ferry cars as well as people. “You just drive on, and the pod departs,” Musk toldBloomberg Businessweek in his first interview about the Hyperloop. . . .