Comment Have to look at the alternatives (Score 5, Informative) 709
Yes, high speed rail is going to be expensive. Yes, it's now projected to cost much more than the original estimate. (The cost has largely increased due to delays (the longer it takes to build a project, the more it costs), particularly fuelled by NIMBY appeasement ("We don't want the train passing near our house!" "But it is much quieter than standard trains and will increase your property values by being near an HSR station." "Build a tunnel!" "Okay, we'll build a tunnel." "The costs on this project are ballooning!").)
But you have to compare the cost to the alternatives. California's freeways and airports are jammed. With increasing population and mobility, something to move people around will have to be built. And the estimated costs to add volume to airports and highways is estimated to be $100-billion as well.
And, to top it off, high speed rail runs on an operational profit. (This means that yearly revenues are higher than yearly costs.) Everywhere. Yes, high speed rail lines run an operational profit in Japan and France, Spain, Russia, Taiwan and car-loving-and-train-hating America. In Britain all rail is private, and for-profit companies are in fierce competition to pay for the rights to run rail services, which are barely at HSR levels if at all. It's a strongly held misconception that rail travel is unprofitable: HSR makes a profit all over the world, and it usually subsidizes local and regional rail transport (which the US has much of).
And though only the Tokyo-Osaka and Paris-Lyon line have paid off all their construction costs, that's because they're the oldest HSR lines; others are on track to in the future. Which modes of transportation don't pay off their construction costs? Oh, that's right, nearly all roads. Remember Carmageddon/The Carpocalypse, when an overpass outside LA was torn down, shutting traffic for the weekend? That was all so they could widen the highway through a mountain pass. Were the anti-HSR people asking for ridership studies for the Sepulveda Pass? Were they asking for the expansion to run an operational profit, let alone an overall profit? Of course not; only rail is subjected to such standards.
Add to this that a train is much more efficient in transporting this number of people, from an energy, environmental and economic perspective, and this is using studies that are assuming that gas prices will be relatively stable over the next few decades.
Obviously there still has to be overview of the project, making sure money is being spent efficiently and for best value. But the entire transportation sector needs to be looked at from this viewpoint. Airlines can work with rail to transport their passengers on their "last mile", freeing up their planes for more profitable medium- and long-haul routes, like done in Germany (Frankfurt Airport has two train stations). Road funds can be diverted to repairing our existing infrastructure as opposed to building more asphalt that needs to be maintained. And everyone will get to where they are going sooner. If this is done, North America will look back 20 years from now, not wondering "How could they do this?", but instead "How did they wait so long?"