I disagree. The US should focus on those routes that there is ample reason to believe there would be high demand for true high speed rail (280km/h average speed including stops). DC to Boston Via NYC for example: there is every reason to believe this could pay for itself running 8 trains per hour all day. Once we have that there are lots of other cities that can be connected and as the network grows the whole becomes more useful. East of the Mississippi the US is about as densely populated as Europe.
If you already have a route in place using that is cheaper, but often you are stuck with decisions that made sense in 1850 when trains didn't go very fast. Where you are building new track is should always be build to 350km/h standards (you run at 300km/h, but build to a higher standard just in case you need to run fast to make up time at the cost of efficiency). There are many towns with populations of 50,000 or so people that you wouldn't build new track too, but if there is existing track running slower trains make sense.
If you already have a route in place using that is cheaper, but often you are stuck with decisions that made sense in 1850 when trains didn't go very fast. Where you are building new track is should always be build to 350km/h standards (you run at 300km/h, but build to a higher standard just in case you need to run fast to make up time at the cost of efficiency). There are many towns with populations of 50,000 or so people that you wouldn't build new track too, but if there is existing track running slower trains make sense.